The Systems Engineering Glossary

A

• Agile Systems Engineering: An iterative, adaptive approach that applies Agile principles to systems development, enabling fast feedback and flexible response to change.

• Architecture: The fundamental structure of a system, including its elements, relationships, and the guiding principles for its design and evolution.

B

• Baseline: A documented and approved configuration of a system or component that serves as a reference for future development and change control.

• Behavioral Model: A model that describes how a system reacts to inputs or events over time; often used to analyze performance and system logic.

C

• Concept of Operations (ConOps): A stakeholder-oriented document that describes the system's intended use and operational scenarios.

• Configuration Management (CM): A structured approach to managing changes to system components and documentation over the entire lifecycle.

D

• Design Review: A structured checkpoint where system design is evaluated for completeness, correctness, and risk prior to moving forward.

• Digital Engineering: An integrated digital approach that uses authoritative data, models, and advanced tools to support systems engineering throughout the lifecycle.

E

• End-to-End: Describes a full system process or capability from input to final output or result, often encompassing multiple subsystems.

• Entity: A defined object, component, or concept within a system model, often used in modeling languages like LML or SysML.

F

• Functional Decomposition: The act of breaking down a complex process or system function into smaller, manageable parts for easier analysis and design.

• Failure Modes and Effects Analysis (FMEA): A proactive method for identifying potential failure points in a system and assessing their impact.

I

• Interface Control Document (ICD): A technical document detailing the boundaries and interactions between different system components or external systems.

• Integration: The process of combining subsystems and components into one system and ensuring they work together as designed.

L

• Lifecycle: The complete span of a system's existence, including conception, design, development, production, operation, maintenance, and retirement.

• LML (Lifecycle Modeling Language): A modeling language specifically designed for systems engineering that balances simplicity and rigor. It integrates requirements, behaviors, risks, verification, and architecture into one semantic framework, often used with tools like Innoslate.

M

• Model-Based Systems Engineering (MBSE): A methodology that uses formal models as the primary artifacts for systems engineering tasks instead of traditional documents.

• Mission Analysis: An early-phase activity to understand the broader problem space, operational context, and stakeholder goals before defining requirements.

N

• Non-Functional Requirement (NFR): A requirement that specifies how a system performs (e.g., reliability, maintainability, performance, scalability, security), rather than what the system does functionally.

O

• Operational View (OV): A description of how the system will operate in its intended environment, often used in architecture frameworks like DoDAF.

P

• Performance Requirement: A specification that defines quantitative performance targets, such as response time, throughput, or efficiency.

• Physical Architecture: A representation of the physical elements (hardware, software, interfaces) of the system and their interconnections.

R

• Requirements Traceability: The ability to link each requirement throughout the lifecycle — from stakeholder need to design, implementation, and verification.

• Risk Management: A continuous process to identify, analyze, monitor, and mitigate risks that may impact project or system success.

S

• Stakeholder: An individual, group, or organization that has a vested interest in the outcome of the system.

• SysML (Systems Modeling Language): A standardized graphical modeling language used in MBSE to specify, analyze, design, and verify complex systems. It supports structural, behavioral, and requirement views through diagrams like Block Definition Diagrams, Activity Diagrams, Sequence Diagrams, and Requirement Diagrams.

• System of Systems (SoS): A collection of independent systems that collaborate to provide capabilities that are not achievable by individual systems alone.

T

• Test and Evaluation (T&E): The process of verifying and validating that a system meets requirements and performs under operational conditions.

• Trade Study: A comparative evaluation of multiple options or solutions based on predefined criteria to support informed decision-making.

V

• Validation: The process of evaluating whether the system meets the intended needs of stakeholders in the real-world environment.

• Verification: The process of confirming that the system design and implementation fulfill the specified requirements.

• V-Model: A visual representation of the systems engineering lifecycle, where each development phase (on the left side) is mirrored by a corresponding testing phase (on the right side).

W

• Work Breakdown Structure (WBS): A hierarchical framework that breaks down the project or system scope into smaller, manageable tasks or components.

📖 Related Reading

• A Beginner's Guide to Systems Engineering