cham n.

title of sovereign princes in Tatar counties, c. 1400, from Turkic, literally "lord, prince," contraction of khaqan "ruler, sovereign." The word has been known in the languages of Europe since 13c.; compare Medieval Latin chanis, Medieval Greek kanes, Old French chan, Russian khanu. In time it degenerated and became a title of respect. The female form is khanum (1824), from Turkish khanim.

"friend, intimate companion," 1680s, originally university slang for "roommate," an alternative spelling of cham, short for chamber(mate); the formation is typical of the late-17c. fondness for clipped words. Among derived forms used 19c. were chumship; chummery "shared bachelor quarters," chummage "system of quartering more than one to a room."