Definition of porphyroid
: a more or less schistose metamorphic igneous or sedimentary rock with porphyritic texture
Start your free trial today and get unlimited access to America's largest dictionary, with:
- More than 250,000 words that aren't in our free dictionary
- Expanded definitions, etymologies, and usage notes
- Advanced search features
- Ad free!
Origin and Etymology of porphyroid
porphyry + -oid
Seen and Heard
What made you want to look up porphyroid? Please tell us where you read or heard it (including the quote, if possible).