use-icon

HOW TO USE THE DICTIONARY

To look up an entry in The American Heritage Dictionary of the English Language, use the search window above. For best results, after typing in the word, click on the “Search” button instead of using the “enter” key.

Some compound words (like bus rapid transit, dog whistle, or identity theft) don’t appear on the drop-down list when you type them in the search bar. For best results with compound words, place a quotation mark before the compound word in the search window.

guide to the dictionary

use-icon

THE USAGE PANEL

The Usage Panel is a group of nearly 200 prominent scholars, creative writers, journalists, diplomats, and others in occupations requiring mastery of language. Annual surveys have gauged the acceptability of particular usages and grammatical constructions.

The Panelists

open-icon

AMERICAN HERITAGE DICTIONARY APP

The new American Heritage Dictionary app is now available for iOS and Android.

scroll-icon

THE AMERICAN HERITAGE DICTIONARY BLOG

The articles in our blog examine new words, revised definitions, interesting images from the fifth edition, discussions of usage, and more.

100-words-icon

See word lists from the best-selling 100 Words Series!

Find out more!

open-icon

INTERESTED IN DICTIONARIES?

Check out the Dictionary Society of North America at http://www.dictionarysociety.com

or 1 (ôr; ər when unstressed)
Share:
conj.
1.
a. Used to indicate an alternative, usually only before the last term of a series: hot or cold; this, that, or the other.
b. Used to indicate the second of two alternatives, the first being preceded by either or whether: Your answer is either ingenious or wrong. I didn't know whether to laugh or cry.
c. Archaic Used to indicate the first of two alternatives, with the force of either or whether.
2. Used to indicate a synonymous or equivalent expression: acrophobia, or fear of great heights.
3. Used to indicate uncertainty or indefiniteness: two or three.

[Middle English, from other, or (from Old English, from oththe) and from outher (from Old English āhwæther, āther; see EITHER).]

Usage Note: When all the elements in a series connected by or are singular, the verb they govern is singular: Tom or Jack is coming. Beer, ale, or wine is included in the charge. When all the elements are plural, the verb is plural. When the elements do not agree in number, some grammarians have suggested that the verb should agree in number with the nearest element: Tom or his sisters are coming. The girls or their brother is coming. Cold symptoms or headache is the usual first sign. Other grammarians, however, have argued that such constructions are inherently illogical and that the only solution is to revise the sentence to avoid the problem of agreement: Either Tom is coming or his sisters are. The usual first sign may be either cold symptoms or a headache. See Usage Notes at and/or, either, neither, nor1.

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
 
-or 1
Share:
suff.
One that performs a specified action: accelerator.

[Middle English -or, -our, from Old French -eor, -eur and Anglo-Norman -our, -ur, all from Latin -or, -ōr-.]

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
 
OR 1 (ôr)
Share:
n.
A logical operator that returns a true value if one or both operands are true.

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
 
or 2 (ôr) Archaic
Share:
conj.
Before. Followed by ever or ere: "I doubt he will be dead or ere I come" (Shakespeare).
prep.
Before.

[Middle English, variant of er, from Old English ǣr, soon, early, and from Old Norse ār; see ayer- in the Appendix of Indo-European roots.]

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
 
-or 2
Share:
suff.
State; quality; activity: valor.

[Middle English -our, from Old French -eur, from Latin -or, -ōr-.]

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
 
OR 2
Share:
abbr.
1. operating room
2. operations research
3. Oregon

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
 
or 3 (ôr)
Share:
n.
Heraldry
Gold, represented in heraldic engraving by a white field sprinkled with small dots.

[Middle English, from Old French, from Latin aurum.]

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. 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:

    Indo-European Roots

    Semitic Roots

    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.