crenelles

Crenelles are small notches along the upper edge of a wall that, together with the solid merlons, form a crenellated parapet. The arrangement—alternating notches (crenelles) and blocks (merlons)—is called crenellation and was a common feature of medieval fortifications, enabling defenders to observe and fire from behind cover.

Etymology: The term crenelle derives from French crénelle, a diminutive of crête, meaning crest or ridge. In English usage the more common terms are crenel and crenellation, but crenelle appears in some historical and regional sources.

Historical use: Crenellations appeared across medieval Europe and were widely implemented in stone castles, city walls, and other defensive structures. They remained a standard element of fortifications from the high Middle Ages into the late medieval and early Renaissance periods, evolving in style but retaining their essential defensive function.

Decorative and heraldic use: Beyond purely military architecture, the crenellated motif appears in decorative mouldings and cornices to evoke a fortress profile. In heraldry, battlemented or crenellated lines may be described as crenellated, signaling a fortress-like edge on shields, coats of arms, or ceremonial insignia.

Related terms: crenel, merlon, embrasure, crenellation.