use-icon

HOW TO USE THE DICTIONARY

Learn what the dictionary tells you about words.

Get Started Now!

Some compound words (like bus rapid transit, dog whistle, or identity theft) don’t appear on the drop-down list when you enter them into the search window. If a compound term doesn’t appear in the drop-down list, try entering the term into the search window and then hit the search button (instead of the “enter” key). Alternatively, begin searches for compound terms with a quotation mark.

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. The Panelists are surveyed annually to gauge the acceptability of particular usages and grammatical constructions.

The Panelists

puzzle-icon

NEED HELP SOLVING A CROSSWORD PUZZLE?

Go to our Crossword Puzzle Solver and type in the letters that you know, and the Solver will produce a list of possible solutions.

open-icon

INTERESTED IN DICTIONARIES?

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

open-icon

AMERICAN HERITAGE DICTIONARY APP

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

scroll-icon

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.

open-icon

OPEN DICTIONARY PROJECT

Share your ideas for new words and new meanings of old words!

Start Sharing Now!

100-words-icon

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

Find out more!

case 1 (kās)
Share:
n.
1. An instance or occurrence of a particular kind or category: a case of mistaken identity. See Synonyms at example.
2. An occurrence of a disease or disorder: a mild case of flu.
3. A set of circumstances or a state of affairs; a situation: It may rain, in which case the hike will be canceled.
4. Actual fact; reality: We suspected the walls were hollow, and this proved to be the case.
5. A question or problem; a matter: It is simply a case of honor.
6. A situation that requires investigation, especially by a formal or official body.
7. Law
a. An action or a suit or just grounds for an action.
b. The facts or evidence offered in support of a claim.
8. A set of reasons or supporting facts; an argument: presented a good case for changing the law.
9. A person being assisted, treated, or studied, as by a physician, lawyer, or social worker.
10. Informal A peculiar or eccentric person; a character.
11. Linguistics
a. In traditional grammar, a distinct form of a noun, pronoun, or modifier that is used to express one or more particular syntactic relationships to other words in a sentence.
b. Case In some varieties of generative grammar, the thematic or semantic role of a noun phrase as represented abstractly but not necessarily indicated overtly in surface structure. In such frameworks, nouns in English have Case even in the absence of inflectional case endings.
Idioms:
in any case
Regardless of what has occurred or will occur.
in case
1. If it happens that; if: In case she dies without heirs, her money will go to charity.
2. To be prepared for the possibility that: bring the charger in case the battery runs low.
3. As a precaution: took along an umbrella, just in case.
in case of
If there should happen to be: a number to call in case of emergency.
off (someone's) case
No longer nagging or urging someone to do something.
on (someone's) case
Persistently nagging or urging someone to do something.

[Middle English cas, from Old French, from Latin cāsus, from past participle of cadere, to fall; see kad- in the Appendix of Indo-European roots.]

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2017 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 
case 2 (kās)
Share:
n.
1. A container; a receptacle: a jewelry case; meat-filled cases of dough.
2. A container with its contents.
3. A decorative or protective covering or cover.
4. A set or pair: a case of pistols.
5. The frame or framework of a window, door, or stairway.
6. The surface or outer layer of a metal alloy.
7. Printing
a. A shallow compartmented tray for storing type or type matrices.
b. The form of a written, printed, or keyed letter that distinguishes it as being lowercase or uppercase: typed the password using the wrong case.
tr.v. cased, cas·ing, cas·es
1. To put into or cover with a case; encase.
2. Slang To examine carefully, as in planning a crime: cased the bank before robbing it.

[Middle English, from Norman French casse, from Latin capsa.]

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2017 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 

This website is best viewed in Chrome, Firefox, Microsoft Edge, or Safari. Some characters in pronunciations and etymologies cannot be displayed properly in Internet Explorer.