"railway maintenance worker," 1918, American English slang, of unknown origin; dancer perhaps from movements required in the work of tamping down ties or pumping a hand-cart, gandy perhaps from the name of a machinery belt company in Baltimore, Maryland.

"the executive branch of the public service," as distinguished from the military, naval, legislative, or judicial, 1765, originally in reference to non-military staff of the East India Company, from civil in the sense "not military." Civil servant is from 1792.

"room appropriated for the reception of company," 1640s, short for withdrawing room (16c.; see withdraw), into which ladies would retire after dinner. Earlier in the sense of "private room" as draw-chamber (mid-15c.); drawyng chaumber (early 15c.).