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FUNCTIONAL SAFETY GLOSSARY

Citation-friendly definitions for HARA, TARA, ASIL, safety goals, traceability, safety cases, and regulated engineering workflows.

Use this glossary as a practical reference for functional safety and cybersecurity terms used in ISO 26262, ISO/SAE 21434, IEC 61508, IEC 61511, and related safety engineering workflows.

ISO 26262Define

HARA

HARA, or Hazard Analysis and Risk Assessment, is the ISO 26262 activity used to identify hazardous events, evaluate severity, exposure, and controllability, derive ASIL, and define safety goals.

ISO 21434Define

TARA

TARA, or Threat Analysis and Risk Assessment, is the ISO/SAE 21434 workflow for identifying assets, damage scenarios, threat scenarios, attack feasibility, impact, risk treatment, and cybersecurity goals.

ISO 26262Define

ASIL

ASIL, or Automotive Safety Integrity Level, is the ISO 26262 risk classification derived from severity, exposure, and controllability ratings for a hazardous event.

IEC 61508 / IEC 61511Define

SIL

SIL, or Safety Integrity Level, is a target level of risk reduction used in functional safety standards such as IEC 61508 and IEC 61511.

Safety AnalysisDefine

FMEA

FMEA, or Failure Modes and Effects Analysis, is a structured method for identifying failure modes, their effects, causes, controls, and risk priorities.

Safety AnalysisDefine

FMEDA

FMEDA, or Failure Modes, Effects, and Diagnostic Analysis, extends FMEA by evaluating diagnostic coverage and failure rates for safety-relevant hardware or systems.

Safety AnalysisDefine

FTA

FTA, or Fault Tree Analysis, is a top-down safety analysis method that models how combinations of faults can lead to an undesired top event.

ISO 21448Define

SOTIF

SOTIF, or Safety of the Intended Functionality, addresses hazards that arise from performance limitations or reasonably foreseeable misuse rather than system faults.

ISO 26262Define

Safety Goal

A safety goal is a top-level safety requirement derived from HARA that defines the safety intent needed to avoid or mitigate an unreasonable risk.

ISO 26262Define

Safety Requirement

A safety requirement specifies a safety-related obligation derived from safety goals, concepts, architecture, or analysis results.

AssuranceDefine

Safety Case

A safety case is a structured argument, supported by evidence, that a system is acceptably safe for its intended use and operating context.

ISO 26262Define

Item Definition

An item definition describes the function, boundaries, interfaces, assumptions, operating modes, and context of the automotive item being analyzed.

ISO 26262Define

Functional Safety Concept

A functional safety concept defines functional safety requirements and preliminary safety measures needed to satisfy safety goals.

ISO 26262Define

Technical Safety Concept

A technical safety concept refines functional safety requirements into technical safety requirements allocated to system elements.

EvidenceDefine

Traceability Matrix

A traceability matrix maps relationships between hazards, threats, goals, requirements, controls, tests, evidence, reviews, and work products.

ISO 26262Define

Confirmation Review

A confirmation review is an independent review activity used in ISO 26262 to evaluate whether selected work products meet their objectives.