tu·ber (tbər, ty-)
a. A swollen, fleshy, usually underground outgrowth of the stem or rhizome of a plant, such as the potato, bearing buds from which new plant shoots arise.
b. A similar outgrowth of a plant root.
2. A rounded projection or swelling; a tubercle.
[Latin tūber, lump; see teuə- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 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.