homology
ho.mol.o.gy \ho--'ma:l-*-je-, h*-\ n 1: a similarity often attributable to
common origin 2a: likeness in structure or function between parts of
different organisms due to evolutionary differentiation from the same or a
corresponding part of a remote ancestor 2b: correspondence in structure
between different parts of the same individ ual 3a: the relation existing
between chemical compounds in a series whose succ essive members have in
composition a regular difference esp. of one carbon and two hydrogen atoms
CH2 3b: the relation existing among elements in the same group of the
periodic table 4: a classification of configurations in topology into
distinct types