Hence prob. chock adv. (XVIII) close (up) to, and in chock-a-block (i) naut., said of a tackle with the two blocks run close together, (ii) gen., crammed close together.
"chock-full." The Concise Oxford Dictionary of English Etymology. . Encyclopedia.com. (January 24, 2019). https://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/chock-full
"chock-full." The Concise Oxford Dictionary of English Etymology. . Retrieved January 24, 2019 from Encyclopedia.com: https://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/chock-full