Definition of protocephalon
1 : the part of an insect embryo that consists of the prostomium and the first postoral somite
2 : the primitive arthropod head corresponding to the sensory as distinguished from the feeding portion of the head of higher forms — compare gnathothorax
Love words? You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.
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 protocephalon
New Latin, from prot- + cephalon
Seen and Heard
What made you want to look up protocephalon? Please tell us where you read or heard it (including the quote, if possible).