'Soffit' definitions:

Definition of 'soffit'

From: WordNet
noun
The underside of a part of a building (such as an arch or overhang or beam etc.)

Definition of 'Soffit'

From: GCIDE
  • Soffit \Sof"fit\, n. [It. soffitta, soffitto, fr. soffiggere to hide, properly, to fix or fasten under, L. suffigere to fasten beneath or below; sub under, beneath + figere to fix, faste: cf. F. soffite.] (Arch.) The under side of the subordinate parts and members of buildings, such as staircases, entablatures, archways, cornices, or the like. See Illust. of Lintel. [1913 Webster]