This type of partnership gained a new term – symbiosis, from the Greek for ‘together’ and ‘living’.13 The word itself was a neutral one, implying any form of coexistence. If one partner benefited at the expense of the other, it was a parasite (or a pathogen if it caused disease). If it benefited without affecting its host, it was a commensal. If it benefited its host, it was a mutualist. All these styles of coexistence fell under the rubric of symbiosis.
