cross-dressing n.

word-forming element typically representing cross as a noun, adverb (cross-examine), adjective (crossbar), and in many words a confluence of them. "There is no distinct line of division between cross as an adjective and cross as a prefix. As a prefix, it often represents the adv. cross, or the prep. cross, across." [Century Dictionary]

mid-14c., "rule, control," verbal noun from dress (v.). In some Middle English uses also short for addressing. In cookery, "sauce used in preparing a dish for the table," from c. 1500. Meaning "bandage applied to a wound or sore" is by 1713.

Dressing-gown "a loose and easy robe worn while applying makeup or doing the hair" is attested from 1777; dressing-room "room intended to be used for dressing" is from 1670s. Dressing-up "act or fact of attiring oneself with attention to style and fashion" is by 1852. Dressing-down (n.) "a reprimand" is by 1839, American English, originally "a thrashing," perhaps ironic or extended from some 19c. mechanical or commercial sense.

"person with a strong desire to dress in clothing of the opposite sex," 1922, from German Transvestit (1910), coined from Latin trans "across, beyond" (see trans-) + vestire "to dress, to clothe" (from PIE *wes- (2) "to clothe," extended form of root *eu- "to dress").

As an adjective from 1925. Transvestism is first attested 1928. Also see travesty, which is the same word, older, and passed through French and Italian; it generally has a figurative use in English, but has been used in the literal sense of "wearing of the clothes of the opposite sex" (often as a means of concealment or disguise) at least since 1823, and travestiment "wearing of the dress of the opposite sex" is recorded by 1832. Among the older clinical words for it was Eonism "transvestism, especially of a man" (1913), from Chevalier Charles d'Eon, French adventurer and diplomat (1728-1810) who was anatomically male but later in life lived and dressed as a woman (and claimed to be one).