homolog /hom″əlog/ [Gk, homos, same] , 1. any organ corresponding in function, origin, and structure to another organ, as the flippers of a seal correspond to human hands. 2. (in chemistry) one of a series of compounds, each formed by an added common atom or atom combination. For example, CH4, methane, is followed by C2H6, ethane, with the addition of a CH2 group. Also spelled homologue. Compare analog. −homologous, adj.
