Meaning of “common” - Learner’s Dictionary

common

adjective uk us /ˈkɒmən/
USUAL

B1 happening often or existing in large numbers:

Injuries are common in sports such as hockey.
→ Opposite uncommon
SHARED

B1 belonging to or shared by two or more people or things:

a common goal/interest
English has some features common to many languages.
common knowledge

B2 something that a lot of people know:

[ + that ] It's common knowledge that he spent time in jail.
ORDINARY [ always before noun ]

not special in any way:

The herbs all have common names and Latin names.
LOW CLASS UK

typical of a low social class:

My mum thinks dyed blonde hair is really common.

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