Glossary · Terminology

ECL

SNOMED CT Expression Constraint Language

Updated

ECL is the SNOMED International query language for selecting a set of SNOMED CT concepts, for example << 73211009 for diabetes mellitus and all its subtypes.

FHIR value sets and terminology servers accept ECL to define intensional value sets, which stay current as each new SNOMED CT release adds concepts.

Official source

SNOMED CT Expression Constraint Language

See also

SNOMED CTValueSet$expandTerminology serverReference set

Explained in depth

Terminology

FHIR terminology servers explained: $lookup, $validate-code, $expand, $translate and $subsumes, with requests

A terminology server holds code systems (SNOMED CT, LOINC, ICD-10), value sets and concept maps and answers questions about codes through FHIR operations. What each operation does, example requests, which servers exist (tx.fhir.org, Ontoserver, Snowstorm, HAPI), and how apps use them.

26 October 2026

Definitions written by Anpheros from the official sources linked on each page. General information about standards and regulation, not legal or medical advice. All terms →

Explore the app

Get started

Devices

More

Tests at home

Free tools

Get started

More

Explore Platform

SDKs and code

More

Read the guides

Explained

More

Research

More