Green’s Dictionary of Slang

beam n.2

[abbr. SE sunbeam; Burley writes ‘bean’ (see bean n.1 (7)) but Major, Juba to Jive: A Dict. of Afro-American Slang (1994) suggests it is a misprint for this]

(US black) the sun.

[US] in ‘Jiver’s Bible’ in D. Burley Orig. Hbk of Harlem Jive.