means The point or boundary beyond which something cannot or may not go, whether in quantity, extent, or behavior.

from From Latin 'limes' (genitive 'limitis'), a word the Romans used for a boundary path, a frontier track, or the marked edge between fields — the same root that gives us 'limitless' and a cousin of 'liminal' (the threshold). It reached English through Old French 'limite' in the late Middle Ages, carrying that sense of a drawn edge.