Greek also had an alpha copulativum, a- or ha-, expressing union or likeness, which is the a- expressing "together" in acolyte, acoustic, Adelphi, etc. It is from PIE root *sem- (1) "one; as one, together with."
c. 1600, from Latin septicus "of or pertaining to putrefaction," from Greek septikos "characterized by putrefaction," from sepein "make rotten or putrid, cause to rot" (see sepsis). Septic tank is attested from 1902.
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Harper, D. (n.d.). Etymology of aseptic. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/aseptic