"to throw," 1590s, variant of chock "give a blow under the chin" (1580s), possibly from French choquer "to shock, strike against," imitative (see shock (n.1)). Related: Chucked; chucking.
"piece of wood or meat," 1670s, probably a variant of chock (n.) "block." "Chock and chuck appear to have been originally variants of the same word, which are now somewhat differentiated." Specifically of shoulder meat from early 18c. American English chuck wagon (1880) is from the meat sense.
"slight blow under the chin," 1610s, from chuck (v.1). Meaning "a toss, a throw" is from 1862. Related: Chucked; chucking.