Gable n. : A cable.

Gable n. : The vertical triangular portion of the end of a building, from the level of the cornice or eaves to the ridge of the roof. Also, a similar end when not triangular in shape, as of a gambrel roof and the like.

Gable n. : The end wall of a building, as distinguished from the front or rear side.

Gable n. : A decorative member having the shape of a triangular gable, such as that above a Gothic arch in a doorway.

Example:
Is it worth the savings in energy cost to install a Gable fan for my attic?

Taxonomy
gable, roof, gable roofs, gable ends, free encyclopedia, shape, tympanum, The House of the Seven Gables, four gables, triangular portion, wind flows, search, Unsourced, free dictionary, edges, structural system, climate, aesthetic concerns.

Defination from the web:
gable is the generally triangular portion of a wall between the edges of a sloping roof. ... Examples of the crow stepped gable can be seen at Muchalls Castle and Monboddo House, both 17th century Scottish buildings. ...