Old English feallan (class VII strong verb; past tense feoll, past participle feallen) "to drop from a height; fail, decay, die," from Proto-Germanic *fallanan (source also of Old Frisian falla, Old Saxon fallan, Dutch vallen, Old Norse falla, Old High German fallan, German fallen, absent in Gothic).
These are from PIE root *pol- "to fall" (source also of Armenian p'ul "downfall," Lithuanian puolu, pulti "to fall," Old Prussian aupallai "finds," literally "falls upon").
Meaning "come suddenly to the ground" is from late Old English. Of darkness, night, from c. 1600; of land sloping from 1570s; of prices from 1570s. Of empires, governments, etc., from c. 1200. Of the face or countenance from late 14c. Meaning "to be reduced" (as temperature) is from 1650s. Meaning "die in battle" is from 1570s. Meaning "to pass casually (into some condition)" is from early 13c.
To fall in "take place or position" is from 1751. To fall in love is attested from 1520s; to fall asleep is late 14c. To fall down is early 13c. (a-dun follon); to fall behind is from 1856. Fall through "fail, come to nothing" is from 1781. To fall for something is from 1903.
To fall out is by mid-13c. in a literal sense; military use is from 1832. Meaning "have a disagreement, begin to quarrel" is attested from 1560s (to fall out with "quarrel with" is from late 15c.).
"to or at the side; by itself, away from others," late 14c., from Old French a part (Modern French à part) "to the side," from Latin ad "to" (see ad-) + partem, accusative of pars "a part, piece, a faction, a part of the body" (from PIE root *pere- (2) "to grant, allot"). The first element is probably felt in English as a- as in abroad, ahead (see a- (1)). As an adjective from 1786.
c. 1200, "a falling to the ground; a dropping from a height, a descent from a higher to a lower position (as by gravity); a collapsing of a building," from Proto-Germanic *falliz, from the source of fall (v.). Old English noun fealle meant "snare, trap."
Of the coming of night from 1650s. Meaning "downward direction of a surface" is from 1560s, of a value from 1550s. Theological sense, "a succumbing to sin or temptation" (especially of Adam and Eve) is from early 13c.
The sense of "autumn" (now only in U.S. but formerly common in England) is by 1660s, short for fall of the leaf (1540s). Meaning "cascade, waterfall" is from 1570s (often plural, falls, when the descent is in stages; fall of water is attested from mid-15c.). The wrestling sense is from 1550s. Of a city under siege, etc., 1580s. Fall guy is attested by 1906.
1540s, "deteriorated condition, decay," from French décadence (early 15c.), from Medieval Latin decadentia "decay," from decadentem (nominative decadens) "decaying," present participle of decadere "to decay," from Latin de- "apart, down" (see de-) + cadere "to fall" (from PIE root *kad- "to fall"). Meaning "process of falling away from a better or more vital state" is from 1620s. Used of periods in art since 1852, on French model.
c. 1600, "composition, act of composing, constructing, arrangement" (also, in early use, with many senses now given to compound (n.2)), from compose + -ure. Sense of "tranquility, calmness, composed state of mind" is first recorded 1660s, from composed "calm" (c. 1600). For sense, compare colloquial fall apart "lose one's composure."
also distil, late 14c., distillen, "to let fall in drops" (transitive); early 15c., "to drop, trickle, drip, fall in drops" (intransitive), from Old French distiller (14c.), from Latin distillare "trickle down in minute drops," from dis- "apart" (see dis-) + stillare "to drip, drop," from stilla "drop," which is of uncertain origin, perhaps from a PIE root *sti-. De Vaan compares Greek stile "drop;" Lithuanian styri "to become stiff," Old Norse stira "to be rigid, stiff," but has doubts about all of them. From late 14c. as "obtain or extract by distillation;" from c. 1400 as "subject to distillation." Related: Distilled; distilling.