"base frame of an automobile," 1903, American English; earlier "sliding frame or carriage-base for a large gun" (1869), "window frame" (1660s), from French châssis "frame," Old French chassiz (13c.) "frame, framework, setting," from chasse "case, box, eye socket, snail's shell, setting (of a jewel)," from Latin capsa "box, case" (see case (n.2)) + French -is, collective suffix for a number of parts taken together. Compare sash (n.2).
"large, loose sash worn as a belt," 1610s, from Hindi kamarband "loin band," from Persian kamar "waist" + band "something that ties," from Avestan banda- "bond, fetter," from PIE root *bhendh- "to bind."
The Irish surname is originally Mc Casmonde (attested from 1429), from a misdivision of Mac Asmundr, from Irish mac "son of" + Old Norse Asmundr "god protector."
1590s, an abusive term for a person, perhaps meaning "a pedant;" c. 1600, "a whim;" 1640s, "pun or word-play," a word of unknown origin, said in 17c. to be Oxford University slang. Perhaps the sort of ponderous mock-Latin word that was once the height of humor in learned circles; Skeat suggests Latin conandrum "a thing to be attempted" as the source. Also spelled quonundrum.
From 1745 as "a riddle in which some odd resemblance is proposed between things quite unlike, the answer often involving a pun." (An example from 1745: "Why is a Sash-Window like a Woman in Labour? because 'tis full of Panes").