1. short for mechanic; a person who repairs or maintains machines or vehicles
Usage: informal; chiefly North American
2. short for mechanics; the branch of physics dealing with motion and forces
Usage: informal; academic

Examples

• I took my car to the mech to get the brakes checked.
• The mech said the engine needs a complete overhaul.
• She's studying mech in her physics class.
• Our team hired a new mech to work in the shop.
• The mech fixed the transmission in just two hours.