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!

sound 1 (sound)
Share:
n.
1.
a. Vibrations transmitted through an elastic solid or a liquid or gas, with frequencies in the approximate range of 20 to 20,000 hertz, capable of being detected by human organs of hearing.
b. Transmitted vibrations of any frequency.
c. The sensation stimulated in the organs of hearing by such vibrations in the air or other medium.
d. Such sensations considered as a group.
2. A distinctive noise: a hollow sound.
3. The distance over which something can be heard: within sound of my voice.
4. Linguistics
a. An articulation made by the vocal apparatus: a vowel sound.
b. The distinctive character of such an articulation: The words bear and bare have the same sound.
5. A mental impression; an implication: didn't like the sound of the invitation.
6. Auditory material that is recorded, as for a movie.
7. Meaningless noise.
8. Music A distinctive style, as of an orchestra or singer.
9. Archaic Rumor; report.
v. sound·ed, sound·ing, sounds
v.intr.
1.
a. To make or give forth a sound: The siren sounded.
b. To be given forth as a sound: The fanfare sounded.
2. To present a particular impression: That argument sounds reasonable.
v.tr.
1. To cause to give forth or produce a sound: sounded the gong.
2. To summon, announce, or signal by a sound: sound a warning.
3. Linguistics To articulate; pronounce: sound a vowel.
4. To make known; celebrate: "Nations unborn your mighty names shall sound" (Alexander Pope).
5. To examine (a body organ or part) by causing to emit sound; auscultate.
Phrasal Verb:
sound off
1. To express one's views vigorously: was always sounding off about higher taxes.
2. To count cadence when marching in military formation.

[Middle English soun, from Old French son, from Latin sonus; see swen- 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.
 
sound 2 (sound)
Share:
adj. sound·er, sound·est
1. Free from defect, decay, or damage; in good condition: Is the bridge sound?
2. Free from disease or injury. See Synonyms at healthy.
3.
a. Marked by or showing common sense and good judgment; levelheaded: a sound approach to the problem.
b. Based on valid reasoning; having no logical flaws: a sound conclusion; sound reasoning. See Synonyms at valid.
c. Logic Of or relating to an argument in which all the premises are true and the conclusion follows from the premises.
4.
a. Secure or stable: a partnership that started on a sound footing.
b. Financially secure or safe: a sound economy.
5. Thorough; complete: gave their rivals a sound thrashing.
6. Deep and unbroken; undisturbed: a sound sleep.
7. Compatible with an accepted point of view; orthodox: sound doctrine.
adv.
Thoroughly; deeply: sound asleep.

[Middle English, from Old English gesund.]

soundly adv.
soundness n.

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2017 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 
sound 3 (sound)
Share:
n.
1. Abbr. Sd.
a. A long, relatively wide body of water, larger than a strait or a channel, connecting larger bodies of water.
b. A long, wide ocean inlet.
2. Archaic The swim bladder of a fish.

[Middle English, from Old English sund, swimming, sea.]

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2017 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 
sound 4 (sound)
Share:
v. sound·ed, sound·ing, sounds
v.tr.
1. To measure the depth of (water), especially by means of a weighted line; fathom.
2. To try to learn the attitudes or opinions of: sounded out her feelings.
3. To probe (a body cavity) with a sound.
v.intr.
1. To measure depth.
2. To dive swiftly downward. Used of a marine mammal or a fish.
3. To look into a possibility; investigate.
n.
An instrument used to examine or explore body cavities, as for foreign bodies or other abnormalities, or to dilate strictures in them.

[Middle English sounden, from Old French sonder, from sonde, sounding line, probably of Germanic origin.]

sounda·ble adj.

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.