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.
v.
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.
adj.
"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.
词根：front = forehead 表示“前额”
affront v. 冒犯，侮辱（ar一再+front→一再到[别人]面前去→冒犯[别人]
confront v. 面临，对抗（con互相，共同+front→互相面对→对抗）
effrontery n. 厚颜无耻（er出+front+ery→前额[脸面]出去不要→不要脸）
词根：front = forehead, face（前, 前面 , 前部, 前额）
来源于古法语或拉丁语 front/frons 意为 forehead,face。
同源词：
1. affront（向某人凑过脸 af<ad(=to) + front(=face,forehead) vt.公然侮辱；勇敢地面对 n.公然悔辱 affrontive adj.侮辱性的 Priests who marry are an affront to the church. 结婚的牧师对教会来说是一种侮辱。
2. confront（一起对顶额头 con<com(=together) + front (=forehead,face) vt.面临；勇敢地面对；对抗 confrontation n.对抗 It's important to confront your fears rather than run from them. 重要的是，你应该勇敢地去面对你内心的恐惧，而不是逃避。
3. effrontery（将额头向外探 ef<ex(=out) + front(=forehead)） n.厚颜无耻（的行为） The doorman had the effrontery to deny me entrance to the hotel. 门卫厚颜无耻地阻止我进饭店。
5. frontier （-ier (n.) 名词后缀） n.边境，国境；（探索活动的）新领域 town on the frontier 国境线上的城市 frontier disputes 边境纷争 frontier incidents 边境（冲突）事件 frontier spirit 开拓精神
6. frontiersman n.边远地区的居民
7. frontispiece n.（书的）卷着插画
8. frontlet n.（丝带等）额饰 *let(=small)
9. forefront （fore 前 / 在…前（形容在最前面的，即最前部 / 最前线）） n.最前面，最前方；最重要的位置 *fore(=before) in the forefront of the battle 在战斗的最前线 in the forefront of my mind 在我心中最重要
〔李〕[front] n.前部； 正面 ←front (F frons)=forehead, foremost part 前额，前部