Cornice is a projecting ornamental molding that crowns a building or wall.
A cornice is the uppermost, horizontally projecting section of a classical entablature, or more generally any molded projection that crowns a wall, door, or window. Functionally, it throws rainwater clear of the façade below; visually, it gives a building a decisive, legible termination against the sky. Ancient Greek temples established the form as part of the entablature sitting atop the columns; Renaissance architects revived it as a way to cap palazzo façades with authority, and cornices became so essential to reading a building's silhouette that entire city streetscapes — Parisian boulevards, Georgian London terraces — were regulated to keep their cornice lines aligned, creating an unbroken horizontal rhythm along the street.