prefix of L. origin meaning "under," from L. preposition sub "under" (also "close to, up to, towards"), from a variant form (*(s)up-, perhaps representing *ex-upo-) of PIE base *upo- "from below," hence "turning upward, upward, up, up from under, over, beyond" (cf. Skt. upa "near, under, up to, on," Gk. hypo "under," Goth. iup, O.N., O.E. upp "up, upward," Hittite up-zi "rises"). Used as a prefix and in various combinations. The original meaning is now obscured in many words from Latin (suggest, suspect, subject, etc.); the prefix is active in Mod. Eng., however, sometimes meaning "subordinate" (as in subcontinent, first recorded 1863) or "inferior" (a sense first attested 1963). Many such words are transparent (e.g. subcommittee, 1610) and etymologies of their root words may be found under those headings. As a word of its own, sub is first recorded 1830, as a shortened form of substitute (originally of printer's substitutes). The verb in this sense is from 1853.