1. Forming a relationship with other parts or quantities; being in proportion.
2. Properly related in size, degree, or other measurable characteristics; corresponding: Punishment ought to be proportional to the crime.
3. Mathematics Having the same or a constant ratio.
One of the quantities in a mathematical proportion.
pro·por′tion·ali·ty (-shə-nălĭ-tē) n.
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.