Glossary

These definitions describe the operating model used throughout the book. Application schemas and framework-specific terminology may distinguish the concepts differently.

Term	Working meaning
Engineering	Defining and justifying how a product will meet its intended need, and supporting its realisation and lifecycle with controlled information and evidence.
Design	The decisions and resulting definition specifying how needs and constraints will be satisfied. Includes architecture, interfaces, analyses and specifications as well as geometry.
MBSE	Model-based systems engineering: using connected system models to support requirements, architecture, analysis and verification/validation across the lifecycle.
Model-based enterprise	The wider operating model connecting engineering models to commercial, manufacturing, operational and support information.
Product definition	Controlled information specifying the product and its applicable requirements, characteristics and interfaces.
Part identity	Identity of a defined kind of item; distinct from its revision and from a particular physical instance.
Revision	A controlled version of a definition.
Occurrence	A use of an item within a particular structure and context.
Physical instance	A particular manufactured or installed item, identified at the required serial/lot granularity.
Baseline	An identified, controlled set of information and relationships established for a defined purpose.
Maturity	Degree of demonstrated readiness for a specified use; not equivalent to a single approval status.
Release	Authorised issue of identified information for a stated use under controlled conditions.
Variant / option	A permitted product alternative / selectable feature; exact modelling semantics must be defined.
Effectivity	Conditions identifying where or when a definition or change applies, such as vehicle, serial, lot or date applicability.
EBOM	Engineering bill of materials: a structured engineering view of product composition.
MBOM	Manufacturing bill of materials: a view of material composition organised for manufacture/assembly.
BOP	Bill of process: operations and relationships defining how a product is to be made or assembled.
Verification	Establishing whether specified requirements are met.
Validation	Establishing whether the product meets the intended need in its intended context.
As-built / as-maintained	Recorded physical configuration at build / following service interventions; neither is established merely by publishing a design BOM.
Analysis-model verification	Checking that a model and its implementation represent the intended equations, logic and assumptions correctly.
Analysis-model validation	Assessing whether a model is adequate for its intended use against relevant evidence; distinct from validating the finished product.
Margin	The separation between a predicted or demonstrated condition and its applicable limit, interpreted with uncertainty and assumptions.
Interface authority	The responsibility and delegated right to decide compatibility across a defined boundary.
Manufacturer part number	A supplier or manufacturer identifier related to, but not necessarily identical with, the enterprise engineering or inventory identity.
Directional interchangeability	Permission for one item or replacement set to replace another in a defined context; the reverse substitution need not be acceptable.
Calibration set	Identified parameter data that shapes software-controlled behaviour and forms part of the applicable configuration.
Conditional use	Permission for a stated action within explicit restrictions, bounds and reassessment conditions.
Exposure owner	The accountable owner of consequences accepted by an early commitment within delegated authority.
Work package	Executable scope with controlled inputs, ownership, resources, outputs and completion evidence.
Responsibility / authority / accountability	The obligation to perform work / permission to decide / answerability for the outcome and its evidence.
Technical baseline	Controlled technical definition against which an engineering decision or assessment is made.
Contractual baseline	Agreed obligations and deliverables whose alteration requires the applicable commercial authority.
Supplier qualification	Evidence that a supplier can perform a defined scope; distinct from approving its design or accepting a shipment.
Configuration reconciliation	Comparing identified views and resolving differences in meaning, applicability, quantity or implementation; not merely matching totals.
Installation event	A record connecting an identified item to its installed position and time, with configuration and supporting evidence.
Record-entry time	When information was recorded; may differ from when the physical event occurred.
Change closure	Confirmation that the specified implementation boundary, dispositions and evidence are complete; approval or release alone is insufficient.
Deferred-action transfer	Accepted reassignment of an outstanding obligation with scope, owner, criteria, due event and return evidence; not proof of physical completion.