Dictionary.net

(biology) not corresponding in structure or evolutionary origin

derived from organisms of a different but related species; "a heterologous graft"

derived from organisms of a different but related species; "a heterologous graft"

not corresponding in structure or evolutionary origin

Applied to dissimilar structures.

Made up of tissue not normal to the part.

Different from or opposed to some standard which has been set up; of a tissue, without an analogue in the other tissues; of a tumor, composed of elements that differ from the normal elements. [Gr.]