A Defect is any output from a service or a product that does not meet the customer required specifications, standards or requirements.  Defects can occur at any stage of a value stream or production process.  A defect is not the same as defective.  There may be more than one defect in a defective product or process.  A Defect is also one of the 8 forms of waste or muda. 

  DMADV is the methodology used when designing new processes that did not exist prior to their design.  

  The DMAIC Method is a problem solving methodology used within a six sigma strategy.  The methodology focuses on improving business processes, specifically through the improvement of quality and reducing variation.  It is an Integral part of six sigma.

  Design for Environment or DFE as it is often referred to as, is a design method which considers the safety, sustainability, health and environmental aspects of a service or a product in the initial phases of development and design.

  Design for six sigma is a method or approach used in designing products and processes which attempts to create and provide products and processes that adhere or comply with six sigma quality or approximately 3.4 defects per million opportunities.

  A dedicated line is one that is configured to run, produce or supply either information or parts one piece at a time.  This allows production to move from station to station at a more rapid pace and ultimately improves quality, efficiency and eliminates waste.  Dedicated lines should be established only after analysis as they often times require larger investments.

  Downtime is the period of time during which a piece of equipment or a machine is not functional or can not work.

  Dependent demand is the demand that is directly related to or derived from the bill of materials structure for other items or end products which are independent demand.

  Demand is an economic principle that describes a consumer's desire or willingness for a specific good or service. Holding all other factors constant, an increase in the price of a good or service will decrease demand, and vice versa.  Demand can also be defined as a quantity of a commodity or service which is either wanted or needed.

A standard that is set to monitor sales data for specific items in forecasting models. The standard is usually set to be tripped or triggered when the demand for a period is different from the forecast by more than some number of mean absolute deviations.