1. A unit of weight formerly used in Spanish-speaking countries, equal to about 11.3 kilograms (25 pounds).
2. A unit of weight formerly used in Portuguese-speaking countries, equal to about 14.4 kilograms (32 pounds).
3. A liquid measure formerly used in Spanish-speaking countries, having varying value but equal to about 16.2 liters (17 quarts) when used to measure wine.
[Spanish and Portuguese, both from Arabic ar-rub', the quarter (of a quintal) : al-, the + rub', quarter; see rbʿ in the Appendix of Semitic 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.