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Old English stille "motionless, stationary," from West Germanic *steljaz (cf. Old Frisian, Middle Low German, Middle Dutch stille, Dutch stil, Old High German stilli, German still), from root *stel- "fixed, not moving, standing" (see stall (n.1)). Meaning "quiet, silent" emerged in later Old English. Euphemistic for "dead" in stillborn, etc. Still small voice is from KJV:
And he said, Go forth, and stand upon the mount before the LORD. And, behold, the LORD passed by, and a great and strong wind rent the mountains, and brake in pieces the rocks before the LORD; but the LORD was not in the wind: and after the wind an earthquake; but the LORD was not in the earthquake: and after the earthquake a fire; but the LORD was not in the fire: and after the fire a still small voice. [1 Kings 19:11-13]
"distilling apparatus," 1530s, from Middle English stillen "to distill" (c.1300), a variant of distillen (see distill).
"quietness, the silent part," c.1600 (in still of the night), from still (adj.). Meaning "ordinary photo" (as distinguished from a motion picture) is attested from 1916.
"to calm," Old English stillan, from stille "at rest" (see still (adj.)). Cognate with Old Saxon stillian, Old Norse stilla, Dutch, Old High German, German stillen. Related: Stilled; stilling.
"even now, even then, yet" (e.g. still standing there), 1530s, from still (adj.) in the sense "without change or cessation, continual" (c.1300); the sense of "even, yet" (e.g. still more) is from 1730. Used as a conjunction from 1722.