Green’s Dictionary of Slang

rack n.2

1. [late 19C] (US) an omnibus.

2. [1930s+] (US) the female breasts, esp. when large and firm.

3. [1940s+] (orig. US milit.) a bed; thus sleep.

4. [1970s+] (US black) a card holding bubble-packed birth control pills.

5. [1970s+] (US drugs) a quantity of drugs, e.g. pills, vials of crack cocaine, etc.

6. [2000s] (US black) of money, a large quantity.

7. [2000s] a hotel.

8. [2010s] (US teen) a case of beer.

In derivatives

racked (adj.)

[1960s+] tired out, exhausted.

In compounds

rack attack (n.)

[1960s+] (US campus) a sudden onset of sleepiness.

rack monster (n.) (US campus)

1. [1960s+] (also pad monster) sleepiness, the result either of boredom or exhaustion.

2. [1970s+] a bed.

rack time (n.)

[1990s+] sleep; a nap.

In phrases

hit the rack (v.)

1. [1960s+] to go to bed.

2. [1960s+] (US/US gay) by ext., to have sexual intercourse.

SE in slang uses

In compounds

rack man (n.) [he deals with the racks of coins]

[1930s+] an official in a crap game who deals with making change, paying winners, etc.

rack pick (n.) [SE rack, i.e. the widely spaced teeth resemble objects hanging from a rack + pick, a pronged instrument]

[1960s+] (US black) a comb designed spec. for use on a natural n. (6) or an afro n. (1) hairstyle.

In phrases

rack (it) (v.) [SE book rack]

[1940s] (US campus) to work hard.