Definition of Orthonectida in English:

Orthonectida

plural noun

Zoology
  • A minor phylum of mesozoan worms which are internal parasites of a range of marine invertebrates.

    • ‘They are now believed to be made up of two, possibly unrelated, groups: the Dicyemida and Orthonectida.’
    • ‘As it turns out, the Orthonectida are almost certainly metazoans, particularly under our stem group definition; but it's anyone's guess whether they, or any other members of the mysterious Mesozoa, are also bilaterians.’

Origin

Modern Latin (plural), from Greek orthos straight + nektos swimming (see nekton).

Pronunciation:

Orthonectida

/ˌɔːθə(ʊ)ˈnɛktɪdə/