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Nous avons beaucoup de points communs.
We have a lot of things in common.
Shared by two or more people or groups; belonging to everyone.
C'est un ami commun à tous les deux.
He is a friend common to both of us.
Often used with 'avoir en commun' (to have in common).
Ordinary, not special or rare; found frequently.
C'est un problème commun.
It is a common problem.
Can imply mediocrity depending on context.
Vulgar, lacking refinement or good taste.
Il a des manières très communes.
He has very common/vulgar manners.
Used pejoratively to describe behavior or speech.
If describing a trait shared by people, use 'commun' as 'shared'. If describing quality, it often means 'ordinary' or 'commonplace'. Check if the context implies possession (shared) or frequency/quality (ordinary).
As an adjective, 'commun' must agree in gender and number with the noun it modifies (e.g., commune, communs, communes).
From Latin 'communis', meaning 'shared by all or many'.
Be careful with the nuance: 'commun' can mean 'shared' (positive/neutral) or 'ordinary/vulgar' (negative). Context determines the tone.