The 1893 citation would appear to be from Farmer and Henley’s Slang and Its Analogues. There’s no citation, just the definition:
Hang out, a residence; a lodging; and (American university) a feast; an entertainment.
Farmer and Henley have an earlier citation of the noun in a different sense:
1852 C. A. Bristed Five Years Eng. University (ed. 2) (Farmer), The fourth of July I celebrated by a hang-out.
Green’s Dictionary of Slang has the following definitions:
1. [mid-19C] (US campus) a party, a celebration.
2. [mid-19C+] a lodging, a place of residence.
3. [late 19C+] a place where a group tends to meet.
Unfortunately, the free version doesn’t give access to the citations. Texas A&M doesn’t subscribe and the University of Toronto has finally cut off my library access, so I can’t see what citations, if any, Green’s has.