noun: (physiology) The (natural or surgical) union of parts of two organisms, especially in such a way as to cause them to share their vascular systems. Organisms so joined then are called parabionts.
noun: The fusion of two embryos to form conjoined twins
noun: A transient physiological state of suspension of obvious vital activities such as to enable an organism to escape the notice of its enemies or to conserve its energy.
noun: (ecology, ethology) A form of symbiosis, typically among ants, in which different species share common nest galleries but maintain distinct broods and do not practice mutualism other than incidentally.
noun: (medicine) An alien form of life within an organism, commonly invasive, such as a growing cancer.
