From "English Language and Usage" site: c.1400, from Middle English chokkeful (“crammed full”), possibly from choke (“cheek”) (see cheek (n.)), equivalent to cheek + full. Or it may be from Old French choquier “collide, crash, hit” [similar to shock]. Middle English chokkeful already had the same meaning as modern chock-full. Both this word and choke “to strangle” likely derive ultimately from Old English words meaning “jaw, cheek.” The end result is the same: a mouthful.
Alternately, chokkeful may derive from a more violent word: forced full.
(Some offer a false etymology based on the kind of chocks used in carpentry and shipbuilding: full up to the chocks, perhaps. However that sense of chock only dates to the 1670s, far too late to influence the Middle English word.)
From "Online Etymology Dictionary" site: c.1400, chokkeful "crammed full," possibly from choke "cheek" (see cheek (n.)). Or it may be from Old French choquier "collide, crash, hit" (13c., Modern French choquer), which is probably from Germanic (cf. Middle Dutch schokken; see shock (n.1)).
- (informal) Containing the maximum amount possible, flush on all sides, jam-packed, crammed.
- That article is chock-full of errors
- 1741, George E. Nitzsche, The General Magazine and Historical Chronicle, University of Pennsylvania. General Alumni Society, pages 251:
- The pages of the diary are chock full of fascinating reports of medical incidents of all sorts.
- 1848, Charles Dickens, Dealings with the Firm of Dombey and Son, Bradbury and Evans, pages 565:
- "Chock full o' science," said the radiant Captain, "as ever he was!"