homology
UK[həʊˈmɒlədʒi]US[hoʊˈmɑːlədʒi]
n
The state of having the same or similar relation, relative position, or structure.
n
(Biology) The existence of shared ancestry between a pair of structures, or genes, in different species.
n
(Chemistry) A structural similarity between compounds in a series, especially between members of the same homologous series.
Morpheme Breakdown
homo
logy
homo
same
logy
study, discourse
Etymology
The term "homology" is a compound formed from two Greek roots, entering English via Latin and French scientific vocabulary. The first element, homo- (same), establishes the core concept of correspondence and sameness. The second element, -logy (study or discourse), frames this concept as a formal subject of systematic inquiry. Originally used in mathematics and general philosophy to denote a formal agreement or correspondence, its meaning was refined in 19th-century biology by Richard Owen to specify structural similarity due to common descent, a definition later solidified by Darwinian evolutionary theory. Thus, the word's logic traces a path from the literal idea of "the study of sameness" to precise technical meanings in science, where it describes deep structural relationships inherited from a common ancestor.
Analysis
Structure: homo (same) + logy (study, discourse)
homo: From Greek homos meaning "same". It functions as a combining form indicating sameness or similarity.
logy: From Greek -logia, from logos meaning "word, reason, discourse". It functions as a suffix denoting a branch of knowledge or study.
Examples
The homology between a human arm and a bat's wing is evidence of their evolutionary relationship.
In algebra, one can observe a clear homology between these two mathematical structures.
The compounds form a homology, each successive member differing by a constant CH2 unit.