Short for 'compensation', referring to something, typically money, awarded to someone as a recompense for loss, injury, or suffering. The company offered a comp to the employee for the overtime hours worked.
Short for 'complementary ticket', referring to a free ticket given to an event. She received a comp to the concert from her friend who works at the venue.
Short for "comprehensive examination", a set of rigorous tests required for advancement or graduation in some academic programs. She spent the entire semester preparing for her comps.
Short for "composition" or "comprehensive layout", an early visual draft of a design or advertisement. The designer showed the client a comp of the new brochure before final approval.