What is Pre-hsm?
1.
A period of time before High School Musical came out, used to easily define the time span you're talking about when you are talking about the cast or anybody who worked on High School Musical--but can also be used in reference to common people
This picture of Zac Efron is pre-HSM, so his hair is not all that great.
GIRL 1: When did you lose your virginity?
GIRL 2: Pre-HSM.
See