Green’s Dictionary of Slang

process n.

[the straightening process]

1. (US black) straightened hair; a hairstyle that involves effort to achieve.

[US]R. Abrahams Deep Down In The Jungle 38: The men have taken to having their hair straightened in a pompadour style, called a ‘process’.
[UK]J. Colebrook Cross of Lassitude 174: They get cleaned up, cured of clap, well fed, and come out with a process.
[US]D. Goines Street Players 8: Patting his hair lightly, pushing the process back in place.
[US]E. Folb Runnin’ Down Some Lines 141: Don’t care how the young lady wear her hair. She kin get down with a fonky natural, [...] else she kin have a righteous process.
[US]Eble Campus Sl. Oct. 4: process – hairstyle that took some work to produce [...] ‘Hey, man, don’t mess with my process.’.

2. attrib. use of sense 1.

[US]F.X. Toole Rope Burns 184: That old white man gonna tear up you process ass.

3. the chemical-based product used to achieve the process.

[US]L. Hairston ‘The Winds of Change’ in Clarke Harlem, USA (1971) 319: Sonny rubbed the process in so thick with his rubber gloves, it started stingin’ a little.