1. The bony or cartilaginous framework that encloses and protects the brain and sense organs of all vertebrates and of one group of nonvertebrates (the hagfishes); cranium.
2. Informal The head, regarded as the seat of thought or intelligence: Use your skull and solve the problem.
3. A death's-head.
[Middle English sculle, probably of Scandinavian origin.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.