Stub entry: single definition derived from the NIST trustworthy-AI glossary; sector-specific readings not yet documented — contributions welcome.
A variable is a characteristic of a unit being observed that may assume more than one of a set of values to which a numerical measure or a category from a classification can be assigned.
NIST AIRC, The Language of Trustworthy AI glossary (public-domain compilation), entry 'variable', definition attributed to OECD