mid-13c., "story of a building;" early 14c., "raised platform used for public display" (also "the platform beneath the gallows"), from Old French estage "building, dwelling place; stage for performance; phase, stage, rest in a journey" (12c., Modern French étage "story of a house, stage, floor, loft"), from Vulgar Latin *staticum "a place for standing," from Latin statum, past participle of stare "to stand," from PIE root *sta- "to stand, make or be firm." Meaning "platform for presentation of a play" is attested from late 14c.; generalized for "profession of an actor" from 1580s.
Sense of "period of development or time in life" first recorded early 14c., probably from Middle English sense of "degree or step on the 'ladder' of virtue, 'wheel' of fortune, etc.," in parable illustrations and morality plays. Meaning "a step in sequence, a stage of a journey" is late 14c. Meaning "level of water in a river, etc." is from 1814, American English.
Stage-name is from 1727. Stage-mother (n.) in the overbearing mother-of-an-actress sense is from 1915. Stage-door is from 1761, hence Stage-Door Johnny "young man who frequents stage doors seeking the company of actresses, chorus girls, etc." (1907). Stage whisper, such as used by an actor on stage to be heard by the audience, first attested 1865. Stage-manage (v.) is from 1871.
hand n.
Old English hond, hand "the human hand;" also "side, part, direction" (in defining position, to either right or left); also "power, control, possession" (on the notion of the hand's grip or hold), from Proto-Germanic *handuz (source also of Old Saxon, Old Frisian, Dutch, German hand, Old Norse hönd, Gothic handus), which is of uncertain origin.
The original Old English plural handa was superseded in Middle English by handen, later hands. Indo-European "hand" words tend to be from roots meaning "seize, take, collect" or are extended from words originally meaning only a part of the hand (such as Irish lam, Welsh llaw, cognate with Latin palma and originally meaning "palm of the hand"). One ancient root (*man- (2)), represented by Latin manus is the source of Old English mund "hand," but more usually meaning "protection, guardianship; a protector, guardian."
Meaning "manual worker, person who does something with his hands" is from 1580s, hence "hired workman" (1630s) and "sailor in a ship's crew" (1660s). Meaning "agency, part in doing something" is from 1590s. Clock and watch sense is from 1570s. Meaning "round of applause" is from 1838. The linear measure of 4 inches (originally 3) is from 1560s, now used only in giving the height of horses. The meaning "playing cards held in one player's hand" is from 1620s; that of "a round at a card game" is from 1620s. Meaning "handwriting" is from late 14c.; also "one's style of penmanship" (early 15c.). The word in reference to the various uses of hands in making a pledge is by c. 1200; specifically "one's pledge of marriage" by late 14c.
First hand, second hand, etc. (mid-15c.) are from the notion of something being passed from hand to hand. At hand is from c. 1200 as "near in time," c. 1300 as "within reach." Out of hand (1590s) is opposite of in hand "under control" (c. 1200). Adverbial phrase hand-over-fist (1803) is nautical, suggestive of hauling or climbing by passing the hands one before the other alternately.
Phrase on the one hand ... on the other hand is recorded from 1630s, a figurative use of the physical sense of hand in reference to position on one side or the other side of the body (as in the lefthand side), which goes back to Old English Hands up! as a command from a policeman, robber, etc., is from 1863, from the image of holding up one's hands as a token of submission or non-resistance. Hand-to-hand "in close contact," of fighting, is from c. 1400. Hand-to-mouth "said of a person who spends his money as fast as he gets it, who earns just enough to live on from day to day" [Bartlett] is from c. 1500. Hand-in-hand attested from c. 1500 as "with hands clasped;" figurative sense of "concurrently" recorded from 1570s.