This is a quaint-sounding expression, which I’m not familiar with and which, coincidentally, was discussed by Michael Quinion a few weeks ago in World Wide Words. The word has the following two senses:<2005 ‘It [[Oxford American Writer’s Thesaurus by David Auburn]] is also CHOCKABLOCK with useful advice: "Novel manages to pack into five positive letters what 'unusual,' 'unfamiliar,' 'unconventional,' 'untested,' 'untried,' 'unknown' and 'unorthodox' have to signal with unwieldy and negative un- prefixes."’—‘New York Times,’ 18 December>
CHOCKABLOCK or CHOCK-A-BLOCK: 1) Nautical – Having the blocks drawn close together, as when the tackle is hauled to the utmost, fully hoisted, hauled tight. <“The two blocks of a tackle in hoisting or hauling are chockablock>. 2a) adjective – very full, crowded, crammed full, crammed together <“Exhibition floors were chockablock with racing and sports cars”—‘New Yorker’>. 2b) adverb – in a crowded manner <“Books piled chockablock on the narrow shelf”> [chock + a- + block; from the position of a tackle when hoisting has reached its limit, with both blocks touching. And possibly a backformation of ‘chockful’ for the ‘crowded' definiton]
World Wide Words by Michael Quinion
[Q] From Dr Anthony Rea: “I live in Australia and a few years ago some friends visiting from Canada were perplexed by my father’s use of the term -a-block, meaning full. For example, “the street was chock-a-block with cars”. Are you able to shed any light on the origin of this phrase?”
[A] Chock-a-block is actually a fairly widely known North American term, I’m told. I know it well and would use it, though there’s a faint air of being slightly out of date about it. In Britain, it’s now common to hear the abbreviated forms chocka (or chocker), which are both from World War Two services’ slang, and in Australia the closely related chockers.
Chock here is the same word as in chock-full, jam-packed full or filled to overflowing. One meaning of chock in the nineteenth century was of two things pressed so tightly against each other that they can’t move. This led to the nautical term that’s the direct origin of the phrase. Block refers to the pulley blocks of the tackle used for various hauling jobs on board ship. These worked in pairs, with the ropes threaded between them. When the men hauling tackle ropes had hoisted the load as far as it would go, the two pulley blocks touched and could move no further. They were then said to be chock-a-block, or crammed together.
The origin of chock is complicated and not altogether understood. It’s clear that there has been some cross-fertilisation between it and chock in the sense of a lump of wood used as a wedge to stop something moving. That’s closely enough related to our sense to make it seem as though it might be the same word. But the experts think that chock in chock-a-block actually came from chock-full.
That has been around at least since 1400. It comes from a different source, the verb chokken, as in the Middle English phrase chokken togeder, crammed together. This in turn may be from an Old French verb choquier, to collide or thrust. One of the problems of working out the origin has been that chock-full has appeared in several different spellings—including chuck-full and choke-full —reflecting users’ uncertainty about where it comes from.
(Merriam-Webster’s and Random House Unabridged Dictionaries, Oxford English Dictionary)<1840 “Hauling the reef-tackles CHOCK-A-BLOCK.”—‘Two Years Before the Mast” by Dana, xxv. page 82>
<1899 “There were 437 arrivals at the Waldorf- Astoria, and at other houses the applications were proportionately great. ‘Turning people away,’ ‘CHOCK A BLOCK,’ ‘Never saw anything like it.’” – ‘New York Times,’ 7 September, page 8>
<1946 “The city's two or three inns were CHOCK-A-BLOCK and men were sleeping three, four and five in a bed.”—‘Then and Now’ by W. S. Maugham, v. page 15>
<1965 “When finished early next year at a cost that may run as high as $100 million, Cam Ranh will be a port the size of Charleston, easing the pressure on Saigon's CHOCKABLOCK facilities.”—‘Time Magazine,’ 22 October>
<2000 “TV and radio are also CHOCKABLOCK with stinging parodies of the self-important International Olympic Committee and Australia's own representatives. 14 ‘Time Magazine,’ September>
<2002 “The book is CHOCK-A-BLOCK full of results, but a unified or cohesive study it is not.”—‘Journal of Economic Literature,’ Vol. 40, No. 3, September, page 943>
Ken G – December 18, 2005