Chock
Middle English: probably from an Old Northern French variant of Old French çouche, çoche ‘block, log’, of unknown ultimate origin.
wiktionary
Middle English, from Anglo-Norman choque (compare modern Norman chouque), from an Old Northern French variant of Old French çouche, çouche(“block, log”), of Celtic origin, from Gaulish *tsukka (compare Breton soc’h(“thick”), Old Irish tócht(“part, piece”), itself borrowed from Proto-Germanic *stukkaz. Doublet of stock.
French choquer. Compare shock (transitive verb).
Onomatopoeic.
etymonline
chock (n.)
1670s, "piece of wood, block" (especially one used to prevent movement), possibly from Old North French choque "a block" (Old French çoche "log," 12c.; Modern French souche "stump, stock, block"), from Gaulish *tsukka "a tree trunk, stump."
chock (adv.)
"tightly, close up against," 1799, back formation from chock-full.
