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



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



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



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


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

Find out more!



Check out the Dictionary Society of North America at

seed (sēd)
n. pl. seeds or seed
a. A mature plant ovule containing an embryo.
b. A small dry fruit, spore, or other propagative plant part.
c. Seeds considered as a group: a farmer buying seed.
d. The seed-bearing stage of a plant: The grass is in seed.
a. A larval shellfish or a hatchling fish: released scallop seed in the bay.
b. An egg or cocoon of certain insects: silkworm seed.
3. Something that resembles a seed, as:
a. A tiny bubble in a piece of glass.
b. Medicine A form of a radioactive isotope that is used to localize and concentrate the amount of radiation administered to a body site, such as a tumor.
a. A source or beginning; a germ: the seed of an idea.
b. A small amount of material used to start a chemical reaction.
c. A small crystal used to start a crystallization process.
5. A cell that disperses, especially a cancer cell that spreads from a primary tumor to another location in the body.
6. Archaic
a. Offspring; progeny.
b. Family stock; ancestry.
c. Sperm; semen.
7. Sports A player who has been seeded for a tournament, often at a given rank: a top seed.
v. seed·ed, seed·ing, seeds
a. To plant seeds in (land, for example); sow.
b. To plant (a crop, for example) as seeds in soil.
2. To remove the seeds from (fruit).
3. To furnish with something that grows or stimulates growth or development: a bioreactor seeded with bacteria.
4. Medicine
a. To disperse to, as cancer cells: organs seeded by circulating tumor cells.
b. To disperse or transfer (cancer cells, for example): a needle biopsy that seeded cancer cells into adjacent tissue; seed stem cells onto collagen gels.
5. Meteorology To sprinkle (a cloud) with particles, as of silver iodide, in order to disperse it or to produce precipitation.
6. Sports
a. To arrange (the drawing for positions in a tournament) so that the more skilled contestants meet in the later rounds.
b. To rank (a contestant) in this way.
7. To help (a business, for example) in its early development.
1. To sow seed.
2. To pass into the seed-bearing stage.
3. Medicine To disperse and often multiply, as cancer cells.
1. Set aside for planting a new crop: seed corn; seed potatoes.
2. Intended to help in early stages: provided seed capital for a fledgling business.
go/run to seed
1. To pass into the seed-bearing stage.
2. To become weak or devitalized; deteriorate: The old neighborhood has gone to seed.

[Middle English, from Old English sǣd, sēd; see sē- 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.

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.