straight perm; hair straightening treatment
A wasei-eigo term for a chemical hair treatment that makes curly or wavy hair straight. Often contrasted with 縮毛矯正, which is a stronger, more permanent straightening process.
wasei-eigo (Japanese-coined English), from straight perm
I got a straight perm at the hair salon.
A straight perm is a treatment that makes frizzy hair straight.