var·i·a·ble (vârē-ə-bəl, văr-)
a. Likely to change or vary; subject to variation; changeable.
b. Inconstant; fickle.
2. Biology Tending to exhibit genetic variation or variation in a physical trait: geographically variable color patterns.
3. Mathematics Having no fixed quantitative value.
1. Something that varies or is prone to variation.
2. Astronomy A variable star.
a. A quantity capable of assuming any of a set of values.
b. A symbol representing such a quantity. For example, in the expression a2 + b2 = c2, a,b, and c are variables.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 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.