Definition of “minor” - Learner’s Dictionary

minor

adjective uk us /ˈmaɪnər/
NOT IMPORTANT

B2 not important or serious:

a minor offence
Most of the passengers suffered only minor injuries.
MUSIC [ always before noun ]

in music, belonging to a key (= set of musical notes) that often produces a sad sound

→ Opposite major adjective

(Definition of “minor adjective” from the Cambridge Learner's Dictionary © Cambridge University Press)