commensal Definition

commensal
adj

1. Said of two organisms of different species: living in close association with each other, with one gaining from the relationship, while the other remains unaffected by it.

noun

1. The organism in a commensal relationship which benefits from it. Compare host¹ (noun 5).

Derivative: commensalism
noun

Such a partnership or association. Compare parasitism, symbiosis (sense 1).

Etymology: 19c in this sense; French, from Latin commensalis, from com- together + mensa table.