prefix meaning "not, without," from Greek a-, an- "not" (the "alpha privative"), from PIE root *ne- "not" (source also of English un-).
In words from Greek, such as abysmal, adamant, amethyst; also partly nativized as a prefix of negation (asexual, amoral, agnostic). The ancient alpha privatum, denoting want or absence.
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."
biotic adj.
"pertaining to life," 1847, also biotical (1847), from Latin bioticus, from Greek biotikos "pertaining to life," from bios "life" (from PIE root *gwei- "to live"). Also see bio-. Biotic factor was in use by 1907. Related: Biotical. Biotics "science of vital functions and manifestations; powers and qualities peculiar to living organisms" (T. Sterry Hunt) is from 1882.