What does deme mean?
A deme is a distinct, localized population within a species whose members interbreed with one another more than they do with outsiders. The concept is central to population genetics, where demes serve as the basic units among which gene flow, drift, and selection are measured; a species may consist of many partially separated demes connected by occasional migration. The word has a second, historical sense: in ancient Attica, a deme was one of the local districts or townships established as administrative and civic units — most famously through Cleisthenes' reforms in the late sixth century BCE — which reorganized Athenian citizenship around place of residence rather than aristocratic clan. Both senses derive from the Greek word dēmos, meaning people or populace, the same root found in democracy. Today, deme is chiefly a scholarly term, appearing in genetics papers, ecology textbooks, and works on classical Athens.
A locally interbreeding population within a species, regarded as a unit of genetic exchange.
"Researchers sampled individuals from five demes along the river valley."
Common in population genetics; often modified as 'local deme' or 'breeding deme'.
One of the local districts or townships of ancient Attica, used as a civic and administrative unit.
"Membership in an Athenian deme determined a citizen's tribal affiliation."
Restricted to classical history and archaeology contexts.
Regular English plural; used freely in both biological and classical contexts.
"The archipelago's bird populations form several isolated demes."
The word 'deme' hides inside 'democracy' — both trace back to the Greek dēmos, meaning the people of a local community.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of deme
Deme comes from Greek dēmos, meaning 'the people', 'populace', or 'district'. It entered English via learned borrowing from Latinized Greek, first in reference to the Athenian townships, and was later adopted by biologists in the nineteenth and twentieth centuries for local interbreeding populations. Cognates sharing this root include democracy ('rule by the people'), demotic ('of the common people'), and epidemic ('upon the people').
How deme is actually used
Primarily a technical term in evolutionary biology, ecology, and classical studies; rarely encountered in everyday speech. The plural 'demes' is standard. In biological writing it often appears with modifiers such as 'local', 'breeding', or 'geographic'.
Easily confused with deme
Deem is a verb meaning to judge or consider, whereas deme is a noun referring to a breeding population or an ancient Greek district.