Word Study
soffit
CIDE DICTIONARY
soffit, 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.].
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]
OXFORD DICTIONARY
soffit, n. the under-surface of an architrave, arch, balcony, etc.
Etymology
F soffite or It. soffitta, -itto ult. f. L suffixus (as SUFFIX)
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