Cleavage is the cleft created by the partial exposure of a woman’s breasts, especially when exposed by low-cut clothing. Décolletage (or décolleté, its adjectival form, in current French) is cleavage produced by a low-cut neckline that exposes the neck, shoulders and parts of the breasts.

Décollatage evolved in Europe during the late middle ages, and evolved with the Victorian swimdress, and is a feature of the unitard, leotard, maillot, and bikini.