Medical Definition of homology
1a: likeness in structure between parts of different organisms due to evolutionary differentiation from the same or a corresponding part of a remote ancestor—compare analogy, homomorphyb: correspondence in structure between different parts of the same individual
2a: the relation existing between chemical compounds in a series whose successive members have in composition a regular difference especially of one carbon and two hydrogen atoms CH2b: the relation existing among elements in the same group of the periodic tablec: similarity of nucleotide or amino acid sequence (as in nucleic acids or proteins)
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