Strategy Bridge

Systems Engineering Glossary

Term Main definition
Trace Deficiency

A trace deficiency exists when a requirement statement cannot be fully traced back to its authorizing source (orphan), or has no path for realization (childless parent).


A visible relationship among two or more logical entities, for example, requirements.

Trade Study

A process to evaluate system alternatives against specific evaluation criteria in order to select the best solution.


The decision-making actions to select the best alternative among multiple options.


The process of moving from one life cycle stage or level of the system hierarchy to another.  The term is often used to refer to the shift from the development environment to the operational environment.


A functional item that can be considered and managed as a separate entity.  It is usually a Configuration Item (CI).

Use Case

Methodology to describe a sequence of actions that provide something of measurable value to an actor (i.e., a role within the system).


An individual or group that uses the system, uses the results of the system, or who benefits from the system.

User Requirements

The user needs expressed in their operational or functional terminology.


The process of proving that a system provides the value intended (capability) and meets the original need defined in the CONOPS. (Did we build the right system?)


The difference between planned and actual parameters.

Vee (System Engineering Vee)

A conceptual model for product development that illustrates the relationship of the system hierarchy to the systems engineering activities throughout the life cycle.


The process of proving that a system meets specifications and requirements.  (Did we build the system correctly?)


A rehearsal or informal meeting held to uncover any issues or inconsistencies prior to a formal review or activity.

Waterfall Development

A linear, sequential product development process that requires successful completion of each life cycle phase prior to proceeding to the next.

Work Breakdown Structure (WBS)

A hierarchical decomposition of the activities required to produce all system entities at a specified level of detail.