Meaning of “gear” - Learner’s Dictionary

gear

noun uk us /ɡɪər/
VEHICLE [ C ]

B2 a set of parts in a motor vehicle or bicycle that control how fast the wheels turn:

to change gear
first/second/third, etc gear

B2 a particular position of the gears in a motor vehicle or bicycle that controls how fast the wheels turn:

The lights turned green, but I couldn't get into first gear.
CLOTHES/EQUIPMENT [ U ]

B2 the clothes and equipment used for a particular purpose:

I've left all my gear at home.

(Definition of “gear” from the Cambridge Learner’s Dictionary © Cambridge University Press)