Systems Engineering Glossary

Term	Definition
Maintainability	The ability, ease, and swiftness to restore a system to functionality after a failure or defect.
Margin	The allowances carried in budget, projected schedules, and technical performance parameters (e.g., weight, power, or memory) to account for risk.
Measure of Effectiveness (MOE)	A measure that indicates how well a system achieves intended operational capabilities in its intended environment.
Measures of Performance (MOP)	Quantifiable measures of how well a system is expected to satisfy defined parameters in its operational environment.
Milestone	A specific definable accomplishment at a given point in time where approval is sought to start or continue into the next phase of the program.
Model	A representation of a real-world process, concept, or system that uses logical expressions to predict how a system might perform under different conditions.
Model-Based Systems Engineering	Formal utilization of models to support all technical Systems Engineering (SE) activities throughout the life cycle phases.
Module	A lower level entity derived from a higher level entity during the architecting process.