Lean Reference

Lean Manufacturing Glossary

A plain-English reference to 143+ lean manufacturing terms, from Toyota Production System roots to today's digital shop floor.

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3 terms

5S: A five-step workplace organization method that creates a clean, safe, and efficient work environment. The five pillars are: Seiri (Sort) – remove unnecessary items; Seiton (Set in Order) – organize tools and materials; Seiso (Shine) – clean and inspect the workplace; Seiketsu (Standardize) – establish consistent standards; and Shitsuke (Sustain) – maintain discipline and continuously follow the 5S principles.
5 Why: A root cause analysis technique used to identify the underlying cause of a problem by repeatedly asking “Why?” until the fundamental issue is discovered. Rather than treating symptoms, the method helps reveal the true source of the problem and supports effective, long-term corrective actions.
Muda(8 Wastes): The eight forms of waste that add cost without creating customer value: Defects, Overproduction, Waiting, Non-Utilized Talent, Transportation, Inventory, Motion, and Overprocessing. Lean also recognizes Muri (Overburden) and Mura (Unevenness) as additional sources of inefficiency that should be minimized.

A

7 terms

A3: A single-page report summarizing a Lean implementation. It includes a defined problem and utilizes the "Plan, Do, Check, Act" cycle along with analysis tools like root cause diagrams and metrics.
A/B Testing(Split Testing): A method of comparing different versions of a product or process simultaneously to determine which performs better.
ABC Analysis: Sequential ordering of product variants by quantity or value sold. The goal is to distinguish high volume parts from low volume parts. 80% of the units or sales are represented by only around 20% of the part types (the “A” parts).
Agile: A project implementation methodology characterized by short, iterative cycles that allow for quick feedback and adjustments.
Andon: A visual management tool that uses lights to indicate the status of a process or operation, facilitating quick responses to issues.
Apparent Efficiency: Refers to increasing production output with no change in the number of workers. It is a numerical increase unrelated to production need based on sales and market demand.
Jidoka(Autonomation): "Automation with a human touch," where machines or team members can detect abnormalities and stop production to address issues, ensuring quality at the source.

B

6 terms

Backflush: The process of automatically decrementing perpetual inventory records based on the bill of materials of a given product. Normally triggered by shipment and invoicing.
Baka Yoke: A variation of Poka-Yoke, this term refers to systems designed to prevent errors by making mistakes obvious, often through simple visual cues.
Batch Processing: A mass production approach where items are produced regardless of immediate demand, leading to overproduction and waste.
Bottleneck(Constraint): The process step with the lowest capacity that limits the throughput of the entire system.
Bottleneck Management: The process of identifying, protecting, exploiting and improving the system constraint.
Built-in Quality: Designing processes so defects cannot continue downstream.

C

17 terms

Capabilities, the Four: As defined by Steven Spear, these include: 1) Designing work to reveal problems; 2) Collaboratively solving those problems; 3) Sharing knowledge across the organization; 4) Developing skills in all team members.
Chaku Chaku: Meaning “load load,” Chaku Chaku is an efficient style of production where machines are arranged in the correct sequence very close together.
Chunking: Breaking down large problems or projects into manageable pieces for easier resolution.
Continuous Flow: A production method that aims for a smooth, uninterrupted flow of products through the manufacturing process, enhancing efficiency and reducing lead times.
Kaizen(Continuous Improvement): A philosophy focused on ongoing enhancements in products, processes, and organizational activities to exceed customer expectations while minimizing waste.
Customer: In Lean terms, any process downstream from the current one. The end customer is the individual or entity that purchases the product or service.
Cycle Time: The total time required to complete a specific step within the value stream.
Capacity: The maximum amount of output a process can produce within a given period.
Capacity Utilization: The percentage of available production capacity that is actually being used.
Cell(Manufacturing Cell): A group of people, machines and equipment arranged to support continuous flow for a product family.
Cellular Manufacturing: Organizing production into cells to reduce transportation, waiting and inventory.
Changeover: The activities required to switch a process from producing one product to another.
Constraint: Any resource that limits the performance of the entire value stream.
Critical Path: The sequence of activities that determines the minimum completion time of a project or process.
Coaching Kata: The leadership practice of coaching others through continuous improvement.
Containment: Temporary actions preventing defective products from reaching customers.
Corrective Action: Actions taken to eliminate the root cause of a problem.

D

3 terms

Drum-Buffer-Rope: A method from the Theory of Constraints for synchronizing production to the constraint while minimizing inventory and work-in-process.
Downtime: Time during which equipment or processes are unavailable for production.
Dock-to-Dock Time: Time from material receipt until finished goods shipment.

E

3 terms

Efficient Islands: A state where resource efficiency is high but flow efficiency is low, leading to isolated, sub-optimized parts.
Efficient Ocean: Flow efficiency is high but resource efficiency is low, focusing on meeting customer needs with flexibility.
Equipment Reliability: A measure of a machine's performance, indicating its ability to operate without failure over a specified period.

F

6 terms

FIFO Lane: First-In-First-Out lane, ensuring that the earliest items processed are the first to be completed.
Fishbone Diagram: Also known as an Ishikawa diagram, this tool helps identify the root causes of a problem by categorizing potential causes.
Flow: The smooth and continuous movement of a process from upstream to downstream. Improving flow reduces waste and enhances efficiency.
Flow Chart: A diagram that visually represents the steps in a process, illustrating each step, decision, or action.
Flow Efficiency: The ratio of value-added time to total lead time, indicating how effectively a process converts inputs into outputs without waste.
First Pass Yield(FPY): The percentage of products that pass through a process correctly without requiring rework.

G

10 terms

Gemba: The "actual place" where work is performed, emphasizing the importance of observing processes firsthand to gather accurate information.
Genbutsu: A Japanese term meaning "the actual object" or "the real thing." Genbutsu emphasizes examining the physical object involved in a process or problem rather than relying on descriptions, photographs or assumptions.
Genchi Genbutsu: Translates to "Go & See." Best practice involves going to the location of the issue to solve the problem quickly and efficiently.
Genchi: A Japanese term meaning "the actual location." Genchi emphasizes going to the exact place where a problem or process occurs to observe the environment firsthand, gain context that data alone cannot provide, and make more informed decisions.
Genjō: The "actual condition" or current state of a process. Genjō emphasizes understanding the situation exactly as it exists - through direct observation and factual data - before making decisions or implementing improvements.
Genjitsu: The actual facts or actual reality of a situation. In lean manufacturing and the Toyota Production System, Genjitsu emphasizes making decisions based on objective evidence rather than assumptions, opinions, or emotions.
Gen’in: The root cause. In lean manufacturing and the Toyota Production System, Gen’in emphasizes identifying the underlying reason why a problem occurred rather than simply addressing its symptoms.
Genji: A Japanese term meaning "the actual time." Genji emphasizes understanding exactly when an event, problem or process occurred so teams can identify patterns and root causes.
Genpō: A Japanese term meaning "the actual method." In lean manufacturing and the Toyota Production System, Genpō emphasizes understanding how work is actually being performed rather than relying only on documented procedures.
Gemba Walk: Leaders regularly visiting the workplace to observe processes, ask questions and support improvements.

H

3 terms

Hansei: A Japanese term meaning “self-reflection” or “introspection.” Hansei is the practice of reflecting on one’s actions, outcomes, and behaviors to recognize mistakes and identify areas for improvement.
Level Production(Heijunka): The practice of leveling production by distributing work evenly over time, helping to reduce lead times and inventory.
Hoshin Kanri: A strategic planning methodology that aligns company objectives from leadership to the shop floor.

I

1 term

Improvement Kata: A scientific routine for achieving target conditions through experimentation.

J

3 terms

Jidoka: The principle of designing equipment to stop automatically and to detect and address problems immediately.
Jishuken: A Japanese lean concept meaning "self-study" or "self-directed improvement." It is a hands-on improvement activity that involves a cross-functional team.
Just-in-Time(JIT): A production strategy that delivers the right amount of product at the right time, combining several Lean principles to optimize efficiency.

K

8 terms

Kaikaku: Radical, revolutionary improvement of a value stream to quickly create more value with less waste.
Kaizen: A process of 'continuous improvement' to ensure maximum quality, eliminate waste, and improve efficiency.
Kamishibai: A visual management tool used for conducting audits, inspections, and accountability checks in a structured way.
Kanban: A visual signaling system that helps manage work and inventory by authorizing the production or movement of products.
Kano Analysis: A technique that categorizes customer feedback into Dissatisfiers, Satisfiers, and Delighters to enhance customer satisfaction.
Karakuri: A traditional Japanese approach to designing mechanical devices that operate without electricity or automation, relying instead on simple mechanics like levers, weights, and pulleys.
Kata: A structured approach to continuous improvement involving steps to understand the current situation, define the desired future state, and iterate toward that goal.
Kitting: A material management method in which all parts, components, tools, and documentation required for a specific product or operation are collected and organized into a single kit before production begins.

L

4 terms

Lead Time: The total time from the moment a customer places an order to the delivery of the product, encompassing both value-added and non-value-added time.
Line Balancing: A technique used to equalize the workload across different steps of a process.
Line Control: A Theory of Constraints technique for controlling machines on synchronized production lines.
Leader Standard Work: Daily, weekly and monthly routines leaders perform to sustain Lean practices.

M

6 terms

Muda: Refers to a wide range of non-value-adding activities or waste.
Mura: Unevenness in production processes, causing inefficiencies and morale issues.
Muri: Overburden or strain, where workers or equipment are required to perform beyond their capacity.
MTTR(Mean Time to Repair): A maintenance performance metric that measures the average time required to repair equipment and restore it to normal operating condition after a failure.
Mixed Model Production: Producing multiple product variants on the same line.
Milk Run: A scheduled transportation route collecting or delivering materials to multiple locations.

N

2 terms

Nemawashi: The process of sharing information about upcoming decisions to involve all employees in the decision-making process.
Net Promoter Score(NPS): A metric measuring customer loyalty and satisfaction.

O

5 terms

One-Piece Flow: A production technique where items move through each production stage individually, promoting flow and minimizing WIP.
Overall Equipment Effectiveness(OEE): Measures how effectively manufacturing equipment is utilized based on Availability, Performance and Quality.
Overall Labor Effectiveness(OLE): Measures workforce productivity by combining availability, performance and quality.
Overall Process Effectiveness(OPE): Measures the effectiveness of an entire production process rather than a single machine.
Obeya: A Japanese term meaning "big room." In lean manufacturing, an Obeya is a dedicated space where cross-functional teams come together to share information, monitor performance, solve problems, and make decisions using shared visual information.

P

12 terms

Poka-Yoke: Techniques designed to prevent errors by making it impossible to perform a task incorrectly.
Pareto Chart: A visual tool that helps identify the most significant factors in a dataset, focusing on the issues that will have the greatest impact when addressed.
Process Map: A visual representation of the sequential flow of a process, highlighting opportunities for improvement.
Pull System: A production strategy where downstream processes signal their needs to upstream activities, allowing production based on actual demand.
Push System: A manufacturing approach that schedules production based on forecasts rather than actual demand.
Policy Deployment: Another name for Hoshin Kanri.
Preventive Action: Actions taken to eliminate potential future problems.
Pitch: The quantity produced within one takt interval.
Pitch Board: Visual planning board showing production progress against takt.
Heijunka Box(Production Leveling Box): Visual scheduling tool used to level production.
Pacemaker Process: The process that sets the production pace for the value stream.
Point of Use Storage(POUS): Keeping materials directly where they are consumed.

Q

2 terms

Quality at the Source: Ensuring every operator verifies quality before passing work to the next process.
Queue Time: Time waiting between process steps.

R

3 terms

Rework: Correcting a defective product so it meets specifications.
Root Cause Analysis(RCA): A structured method for identifying the underlying cause of problems rather than treating symptoms.
Route Train: A standardized logistics route supplying production areas.

S

17 terms

Sort(Seiri): The first pillar of 5S. Eliminate unnecessary items from the workspace so that only what is truly needed remains.
Set in order(Seiton): The second pillar of 5S. Organize needed items so they are easy to find, use and return - a place for everything and everything in its place.
Shine(Seiso): The third pillar of 5S. Clean and inspect the workspace daily to detect early signs of defects, wear and abnormalities.
Standardize(Seiketsu): The fourth pillar of 5S. Create consistent procedures and visual standards that make the first three steps repeatable across every shift.
Sustain(Shitsuke): The fifth pillar of 5S. Form the habit of maintaining the 5S process without needing to be told - discipline becomes culture.
SIPOC: A high-level visual tool outlining Suppliers, Inputs, Process steps, Outputs, and Customers, providing a clear overview of a process.
SMED(Single-Minute Exchange of Dies): A methodology aimed at reducing changeover times to facilitate faster transitions between production runs.
SMART Goals: A structured approach to goal setting, ensuring that objectives are Specific, Measurable, Achievable, Relevant, and Time-bound.
Spaghetti Diagram: A visual representation of a process that traces the movement of products, helping to identify wasteful paths.
Standard Operating Procedure(SOP): A documented process that outlines standardized methods for performing tasks.
Supermarket: A controlled inventory system where a predetermined amount of stock is maintained to meet downstream demand.
Swim Lane Chart: A flowchart that delineates process steps by department or team, clarifying roles and identifying potential wastes.
Scrap: Material that cannot be economically repaired or reused.
Standard Work: The documented best-known method for safely performing a task using the correct sequence, timing and inventory.
Standard Work Combination Sheet: A Lean document showing manual work, machine time and walking time together.
Standard Work Chart: Visual representation of operator movement, machine locations and work sequence.
Standard Work in Process(SWIP): The minimum amount of material required to maintain continuous flow.

T

7 terms

Takt Time: The maximum allowable time to produce one unit of product based on customer demand, guiding production pacing.
Theory of Constraints: A management philosophy that focuses on identifying and managing the bottleneck in a process to improve system performance.
Total Productive Maintenance(TPM): A proactive maintenance strategy to improve machine reliability and performance through routine care.
True Efficiency: Producing the number of parts that can be sold while using the minimum resources possible, a concept focused on cost reduction.
Throughput: Amount of finished product produced within a given time.
Throughput Time: Total elapsed time for a product to move through the process.
Touch Time: Actual hands-on working time.

V

7 terms

Value: Defined by the customer, value refers to aspects of a product or service that customers are willing to pay for.
Value Stream: The series of activities required to deliver a product or service, identifying all steps that add value in the eyes of the customer.
Visual Factory: A workplace where abnormalities can immediately be identified through visual management.
Visual Management: Using visual controls to communicate standards, status and abnormalities.
Visual Controls: Signs, labels, boards and indicators that help operators understand process conditions instantly.
Voice of the Customer(VOC): Capturing customer needs to ensure improvements create value.
Voice of the Process(VOP): Using process data to understand actual performance.

W

5 terms

Work Sequence: The precise order in which tasks are performed.
Work Instruction(WI): Detailed instructions explaining exactly how a task should be performed.
Work in Progress(WIP): Products currently being processed but not yet completed.
Mizusumashi(Water Spider): A material handler responsible for replenishing production without interrupting operators.
Waiting Time: Time when no value is being added.

Y

2 terms

Yamazumi Chart: A visual chart comparing operator workloads to identify imbalance.
Yokoten: The practice of sharing successful improvements across departments or facilities.

Z

1 term

Zero Defects(ZD): A quality philosophy that aims to prevent defects rather than detect or correct them later. It emphasizes doing the work correctly the first time, every time, and building quality into every process.