Definition of Oligochaeta in English:


plural noun

  • A class of annelid worms which includes the earthworms. They have simple setae projecting from each segment and a small head lacking sensory appendages.

    • ‘In traditional classification schemes, the Annelida consists of the Polychaeta and the Clitellata (the latter including the Oligochaeta and Hirudinida).’
    • ‘Stewart affectionately describes him as an elderly man - ‘a dabbler, a homebody’ - pottering about observing members of the taxonomic class Oligochaeta as they went about their business.’
    • ‘The phylum Annelida is traditionally divided into three classes: Oligochaeta, Hirudinida, and Polychaeta (marine annelids).’
    • ‘Annelids with a clitellum (a swelling towards the head of the animal, where the gonads are located) are classified in the Clitellata, which is further divided into Hirudinea and Oligochaeta (including the earthworms).’


Modern Latin (plural), from oligo- ‘few’ + Greek khaitē ‘long hair’ (taken to mean ‘bristle’), because they have fewer setae than polychaetes.