anagenesisPronunciation: /ˌanəˈdʒɛnɪsɪs/Definition of anagenesis noun [mass noun] Biology species formation without branching of the evolutionary line of descent. Derivatives anageneticPronunciation: /-dʒəˈnɛtɪk/ adjective Origin: late 19th century: from ana- and genesisanagenesis in other Oxford dictionaries Definition of anagenesis in the US English dictionary