Soffit (from French soffite, Italian soffitto, formed as a ceiling; directly from suffictus for suffixus, Latin suffigere, to fix underneath), in architecture, describes the underside of any construction element. Examples of soffits include:

• the underside of an arch or architrave (whether supported by piers or columns),
• the underside of a flight of stairs, under the classical entablature,
• the underside of a projecting cornice, or
• the underside of a ceiling to fill the space above the kitchen cabinets, at the corner of the ceiling and wall.