(1):

(n.) That which is analogous to, or corresponds with, some other thing.

(2):

(n.) A word in one language corresponding with one in another; an analogous term; as, the Latin "pater" is the analogue of the English "father."

(3):

(n.) An organ which is equivalent in its functions to a different organ in another species or group, or even in the same group; as, the gill of a fish is the analogue of a lung in a quadruped, although the two are not of like structural relations.

(4):

(n.) A species in one genus or group having its characters parallel, one by one, with those of another group.

(5):

(n.) A species or genus in one country closely related to a species of the same genus, or a genus of the same group, in another: such species are often called representative species, and such genera, representative genera.