late 13c., "round wooden tub," perhaps from Middle Dutch kitte "jug, tankard, wooden container," of unknown origin. Meaning "collection of personal effects," especially for traveling (originally in reference to a soldier), is from 1785; that of "outfit of tools for a workman" is from 1851. Of drum sets, by 1929. Meaning "article to be assembled by the buyer" is from 1930s.
"small fiddle used by dancing teachers," 1510s, probably a shortening of Old English cythere, from Latin cithara, from Greek kithara (see guitar).