three quarters (of a peck), n. — Green’s Dictionary of Slang

three quarters (of a peck) n.

[rhy. sl.]

the neck.

1857		‘Ducange Anglicus’ Vulgar Tongue 37: Three-Quarters of a Peck. Neck [...] ‘Take the measure, Charley, from his three-quarters.’.
1859, 1860		Hotten Dict. of Modern Sl. etc.
1873		Sl. Dict.
1890–1904		Farmer & Henley Sl. and Its Analogues.
1935		A.J. Pollock Und. Speaks.
1942		D. Runyon in Star (Marion, OH) 31 July 6/8: ‘Three quarters of a peck’ means, for some unfathomable reason, the neck.