Short definition
A French wine estate that grows its own grapes and makes wine on the property, equivalent to "estate" in English.
A domaine grows, vinifies, and bottles everything under one roof. In Burgundy, a domaine might own tiny parcels across many appellations — Domaine de la Romanée-Conti has holdings in eight Grand Cru vineyards. In the Rhône, Loire, and Alsace, domaine is also the common term. Bordeaux uses "château" instead, even when the property has no actual castle. Same concept, different word.