The English word ‘Communication’ is derived from the words

Concept

Etymology identifies a word’s historical source forms and their meanings.

A noun may descend from a verb, and that verb from an adjective or root; the related meanings should form a coherent semantic chain.

Application

For communication, the Latin adjective communis means “common” or “shared.” The related verb communicare means “to make common, share, or impart.” Latin communicatio, and then the English word communication, developed along this chain.

Contrast

• Communist and commune are later words associated with political identity or a community; they are not the cited Latin source pair.

• Communism and communalism name modern social or political doctrines rather than the source forms of the English word.

• Communion denotes sharing or fellowship, while common sense denotes practical judgment; this is not the historical source pair.

Result

The required pair is Communis and Communicare.