Fascia is an architectural term for a vertical frieze or band below the edge of a roof, or that forms the outer surface of a cornice, visible to an observer.[1]​.

The word fascia is derived from the Latin fascia which means band, bandage, ribbon or fringe. The term is also used, although less frequently, for other similar band-shaped surfaces, such as a wide, flat strip of molding around a front door, distinct and set off from the wall surface.[2]​.

When it is part of a roof, it usually consists of a wooden board, PVC or galvanized metal sheet. Many of the stone fascias form an ornately carved or assembled cornice, in which case the term fascia is rarely used.

The horizontal fascia board that covers the end of the rafters on the outside of a building (tapacán), can be used to support the gutter. The finished surface below the fascia and joists is called the soffit or cornice.

In classical architecture, the fascia is the broad, simple band (or bands) that make up the architrave section of the entablature, directly above the columns, in both the Ionic order and the Corinthian order. On the other hand, in the Doric order there was a thin band in relief called the tapeworm "Taenia (architecture)"), which was mounted on the board below the triglyph and immediately above the drops "Gota (architecture)"). The term fascia can also refer to the flat band located below the cymatium.[3]​.