front (n.) Look up front at Dictionary.com
late 13c., "forehead," from Old French front "forehead, brow" (12c.), from Latin frontem (nominative frons) "forehead, brow, front; countenance, expression (especially as an indicator of truthfulness or shame); facade of a building, forepart; external appearance; vanguard, front rank," a word of "no plausible etymology" (de Vaan). Perhaps literally "that which projects," from PIE *bhront-, from root *bhren- "to project, stand out" (see brink). Or from PIE *ser- (4), "base of prepositions and preverbs with the basic meaning 'above, over, up, upper'" [Watkins, not in Pokorny].

Sense "foremost part of anything" emerged in the English word mid-14c.; sense of "the face as expressive of temper or character" is from late 14c. (hence frontless "shameless," c.1600). The military sense of "foremost part of an army" (mid-14c.) led to the meaning "field of operations in contact with the enemy" (1660s); home front is from 1919. Meaning "organized body of political forces" is from 1926. Sense of "public facade" is from 1891; that of "something serving as a cover for illegal activities" is from 1905. Adverbial phrase in front is from 1610s. Meteorological sense first recorded 1921.
front (v.) Look up front at Dictionary.com
1520s, "have the face toward," from Middle French fronter, from Old French front (see front (n.)). Meaning "meet face-to-face" is from 1580s. Meaning "serve as a public facade for" is from 1932. Related: Fronted; fronting.
front (adj.) Look up front at Dictionary.com
"relating to the front," 1610s, from front (n.). Front yard first attested 1767; front door is from 1807. The newspaper front page is attested from 1892; as an adjective in reference to sensational news, 1907.