chock-full

chock-full, choke-full, a.
  (ˈtʃɒkfʊl, ˈtʃəʊkfʊl)
  Forms: 5 chokke-fulle, (cheke-full), 8 chocque-, 7– choke-, 8– chock-, choak-, chuck-full.
  [The phonetic form and spelling and the derivation are alike unsettled, the uncertainty of the latter involving that of the former. In Dictionaries, first in Todd (1818) as choke-full (with mention of chuck-full as a ‘corruption’). Subsequent dictionaries have choke-full as main form, with chock-full as a recognized variant. But the American lexicographers have chock-full as the standard form, with choke-full as a cross-reference; and this appears to agree with literary usage in U.S. Choke-full appears to be rather the more frequent in literary use in England; but chock-full is almost universal in spoken use; chuck-full, in literary use bef. and after 1800, is now only dialectal.
  The uncertainty begins with the first appearance of the word as chokke-fulle, cheke-fulle in the alliterative Morte Arthur, the spelling of which is very insecure. Conjectural derivations are from choke v. (ME. choke, cheke) with sense ‘full to choking’, or ‘choked full’; from cheek (ME. cheke, choke n.²) or the related chokes = chops, fauces, with sense ‘full to the chops’; from ME. chok, chokke ? to thrust, ram in, in sense ‘crammed full’. Either of the two former derivations would give an original long ō (which might perhaps, however, be shortened in the combination); the third would give short ŏ from the beginning. Prob. there is a recent association with chock n. and v., in some of their senses, but the latter are too late to be the origin; it is more likely that these senses have been developed under the influence of chock-full: see chock adv. In Eng. dial. glossaries, chock-full is recorded from Lancashire, Cheshire, Sheffield, Whitby, Holderness, Leicester, Warwicksh., Worcester, Berks, Kent; and correspondents send it as the current form in Cornwall, Somerset, Wilts, Surrey, Warwicksh., Staffordsh., Derby, Notts, E. & S. Lincoln, Rossendale, Westmorland, Durham, Northumberland, Scotland, ‘all parts of Ireland’, and ‘among all English soldiers in the army’. Chuck-full is in the Holderness Gloss., and is reported from Norfolk, Suffolk, E. London, Oxford, N. & E. Devon, and in the U.S. Choke-full appears to have no local status. As the local pronunciation is usually entirely distinct from that of choke (choäk, chooäk, chowk, etc.), the two words are not associated, and app. have nothing to do with each other; choke-full being thus merely a book-spelling founded upon a conjectural derivation.]
  Filled so as to leave no vacant space; cram-full; stuffed full; full to suffocation.
  (α) chock-full.

Oxford English Dictionary