(education) core curriculum (courses or other components of an educational program which are foundational, prerequisite, or mandatory, as opposed to the elective, secondary, or variable components of a program)

common fig (Ficus carica)

out of the ordinary, out of the common, exceptional

(linguistics) Proto-Indo-European (reconstructed language)

plural of transport en commun

public transport

(with the definite article le) the ordinary people, the common people, hoi polloi

by mutual agreement, by common consent, consensually

(mathematics) greatest common divisor

(mathematics) least common multiple