Definition of porphyroid in English:

porphyroid

noun

Geology
  • A rock having a porphyritic texture, especially one which is metamorphic in origin.

adjective

Geology
  • Porphyritic.

Origin

Late 18th century; earliest use found in Richard Kirwan (1733–1812), chemist and mineralogist. From porphyr- + -oid.

Pronunciation

porphyroid

/ˈpɔːfɪrɔɪd/