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

as 1 (ăz; əz when unstressed)
1. To the same extent or degree; equally: The child sang as sweetly as a nightingale.
2. For instance: large mammals, as the bear or lion.
3. When taken into consideration in a specified relation or form: this definition as distinguished from the second one.
1. To the same degree or quantity that. Often used as a correlative after so or as: You are as sweet as sugar. The situation is not so bad as you suggest.
2. In the same manner or way that: Think as I think.
3. At the same time that; while: slipped on the ice as I ran home.
4. For the reason that; because: went to bed early, as I was exhausted.
5. With the result that: He was so foolish as to lie.
6. Though: Great as the author was, he proved a bad model. Ridiculous as it seems, the tale is true.
7. In accordance with which or with the way in which: The hotel is quite comfortable as such establishments go. The sun is hot, as everyone knows.
8. Informal That: I don't know as I can answer your question.
1. That; which; who. Used after same or such: I received the same grade as you did.
2. Chiefly Upper Southern US Who, whom, which, or that: Those as want to can come with me.
1. In the role, capacity, or function of: acting as a mediator.
2. In a manner similar to; the same as: On this issue they thought as one.
as is Informal
Just the way it is, with no changes or modifications: bought the samovar as is from an antique dealer.
as it were
In a manner of speaking; as if such were so.

[Middle English, from Old English ealswā; see ALSO.]

Usage Note: Your mother is just as proud as me, said the father to the child with good grades. But should he have said, Your mother is just as proud as I? As with similar constructions using than, a traditional rule states that the pronoun following as ... as ... constructions must be in the nominative case because She is just as proud as I is really a truncated version of the sentence She is just as proud as I am. Another way to view this situation is to say that the second as functions as a conjunction, not as a preposition, in these sentences. Whatever the merits of this logic, the as me construction is very common in speech and appears regularly in the writing of highly respected writers. Moreover, it can be argued that the second as is really a preposition in these constructions and so requires the objective case. There is the further objection that as I constructions are overly formal, and even pretentious. In short, both constructions are defensible, and both are subject to attack. The safe bet is to include the final verb to make a clause: She is just as proud as I am. · In many dialects, people use as in place of that in sentences like We are not sure as we want to go or It's not certain as he left. But this use of as is limited mostly to speaking, and it will likely seem inappropriate in formal writing. · Some nonstandard varieties of American English differ from the standard language in the form and usage of relative pronouns. Where Standard English has three relative pronounswho, which, and thatregional dialects, particularly those of the South and Midlands, allow as and what as relative pronouns: "They like nothing better than the job of leading off a young feller like you, as ain't never been away from home much" (Stephen Crane, The Red Badge of Courage). The car what hit him never stopped. · When as expresses a causal relation, it should be preceded by a comma, as in She won't be coming, as we didn't invite her. When as expresses a time relation, it is not preceded by a comma: She was finishing the painting as I walked into the room. When an as-clause begins a sentence, it may be necessary to make clear whether as is used to mean "because" or "at the same time that." The sentence As they were leaving, I walked to the door may mean either "I walked to the door because they were leaving" or "I walked to the door at the same time that they were leaving." · As is sometimes used after verbs like consider, deem, and account, as in The paintings are considered as masterpieces in their home country. The measure was deemed as unnecessary. This usage may have arisen by analogy to the long-established use of as after regard and esteem in standard contexts: We regarded her as the best writer among us. In our 2009 survey, however, more than 80 percent of the Usage Panel rejected sentences in which as followed consider in this way, including the sentence just quoted. These constructions bear the stigma of redundancy and should be avoided in careful writing. See Usage Notes at because, equal, like2, so1.

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.