Definition of pyrenoid in US English:

pyrenoid

noun

  • Botany. A small spherical or elliptical structure found in the chloroplasts of many algae and hornworts, associated with carbon fixation and starch deposition.

Origin

Mid 19th century (in an earlier sense). From post-classical Latin pyrenoides from Hellenistic Greek πυρηνοειδής shaped like a fruit-stone from ancient Greek πυρήν fruit-stone + -οειδής. In use as noun after German Pyrenoid.

Pronunciation

pyrenoid

/ˈpʌɪrənɔɪd/