for·ti·tude (fôrtĭ-td′, -tyd′)
Strength of mind that allows one to endure pain or adversity with courage.
[Middle English, from Latin fortitūdō, from fortis, strong; see bhergh-2 in the Appendix of Indo-European roots.]
for′ti·tudi·nous (-tdn-əs, -tyd-) adj.
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.