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

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

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

gas (găs)
Share:
n. pl. gas·esor gas·ses
1.
a. The state of matter distinguished from the solid and liquid states by relatively low density and viscosity, relatively great expansion and contraction with changes in pressure and temperature, the ability to diffuse readily, and the spontaneous tendency to become distributed uniformly throughout any container.
b. A substance in the gaseous state.
2. Any of various mixtures of flammable gases used for lighting, heating, or cooking.
3. Gasoline.
4. The speed control of a gasoline engine. Used with the: Step on the gas.
5. A gaseous asphyxiant, irritant, or poison.
6. A gaseous anesthetic, such as nitrous oxide.
7.
a. Flatulence.
b. Flatus.
8. Slang Idle or boastful talk.
9. Slang Someone or something exceptionally exciting or entertaining: The party was a gas.
v. gassed, gas·sing, gas·esor gas·ses
v. tr.
1. To treat chemically with gas.
2. To overcome, disable, or kill with poisonous fumes.
v. intr.
1. To give off gas.
2. Slang To talk excessively.
Phrasal Verb:
gas up
To supply a vehicle with gas or gasoline: gas up a car; gassed up before the trip.

[Dutch, an occult physical principle supposed to be present in all bodies, alteration of Greek khaos, chaos, empty space, coined by Jan Baptista van Helmont (1577-1644), Flemish chemist.]

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:

    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.

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.