Alexander (Hamilton), n. — Green’s Dictionary of Slang

Alexander (Hamilton) n.

[the picture of the US politician, Alexander Hamilton (1757–1804), is printed on the note]

1. (US) a $10 bill.

1953		‘John Eagle’ Hoodlums (2021) 61: Four hundred ten times, a phony Alexander had passed over the counter.
1967–70		in DARE questionaire.

2. (US) one’s signature [a confusion with John Hancock n.].

1966

in DARE.