protect: [16] The -tect element of protect goes back to the past participle of Latin tegere ‘cover’ (source of English integument [17] and toga [16] and related to thatch). Combination with the prefix prō- ‘in front’ produced prōtegere ‘cover in front, protect’. Another English product of the past participle tectus is detect [15]. => detect, integument, thatch, toga[protect etymology, protect origin, 英语词源]
mid-15c., from Latin protectus, past participle of protegere "to protect, cover in front" (see protection). International economics sense from 1789. Related: Protected; protecting.