Commensalism: A symbiotic relationship in which one organism benefits from the relationship, while the other is not significantly helped or harmed.
Competition: Groups or individuals within a species contend for available food or territory, with those from another species.
Endosymbiosis: A symbiotic relationship in which one symbiont lives within the tissues of the other.
Facultative Mutualism: Symbionts which do not rely on each other for their existence, but chose to interact as a matter of the benefit gained (for at least one member of the pair).
Host: Most often associated with the victim of a parasitic relationship, it can also refer to any mutualistic or commensal symbiont which provides something of value.
Obligate Mutualism: Both symbionts depend entirely upon each other for their survival.
Mutulistism: A symbiotic relationship in which both symbionts gain benefit from the interaction.
Parasitism: A symbiotic relationship in which only one member of the association benefits, whereas the other is harmed.
Predation: The predator/prey relationship entails the consumption of individuals from one species by those of another.
Phoresis: The transportation of a member of one species to another location by a different organism. This may have mutualistic results or it could be commensal.
Symbiont: Member of a symbiotic relationship
Symbiosis: The physical interaction of two different species of biological organisms.