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so 1 (sō)
a. To the amount or degree expressed or understood; to such an extent: She was so happy that she cried.
b. To a great extent; to such an evident degree: But the idea is so obvious.
2. Afterward; then: to the gas station and so home.
3. Used to preface a remark or signal a new subject: So what happened here? So I'm going to the store to buy some milk.
4. In the same way; likewise: You were on time, and so was I.
5. Apparently; well, then. Used in expressing astonishment, disapproval, or sarcasm: So you think you've got troubles?
a. In truth; indeed; assuredly: "You aren't right." "I am so!"
b. Informal Used as an intensive, especially with verbs or verb phrases: They want to move in with us, but that is so not going to happen.
7. In the condition or manner expressed or indicated; thus: Hold the brush so.
1. True; factual: I wouldn't have told you this if it weren't so.
2. In good order: Everything on his desk must be exactly so.
1. For that reason; therefore: This is the easiest way to get there, so don't argue.
2. With the result or consequence that: He failed to appear, so we went on without him.
3. With the purpose that: I stayed so I could see you.
Such as has already been suggested or specified; the same or roughly the same: She became a loyal friend and remained so.
Used to express surprise or comprehension: So! You've finished your work at last.
so as to
In order to: Mail your package early so as to ensure its timely arrival.
so that
1. With the purpose that: I stopped so that you could catch up.
2. With the result or consequence that.
so what
Used to express contempt or lack of interest.

[Middle English, from Old English swā; see swo- in the Appendix of Indo-European roots.]

Usage Note: Many critics and grammarians have insisted that so must be followed by that in formal writing when used to introduce a clause giving the reason for or purpose of an action: He stayed so that he could see the second feature. But since many respected writers use so for so that in formal writing, it seems best to consider the issue one of stylistic preference: The store stays open late so (or so that) people who work all day can buy groceries. Both so and so that are acceptably used to introduce clauses that state a result or consequence: The Bay Bridge was still closed, so (or so that) the drive from San Francisco to the Berkeley campus took an hour and a half. · Critics have sometimes objected to the use of so as an intensive meaning "to a great degree or extent," as in We were so relieved to learn that the deadline had been extended. This usage is most common in informal contexts, perhaps because, unlike the neutral very, it presumes that the listener or reader will be sympathetic to the speaker's evaluation of the situation. Thus one would be more apt to say It was so unfair of them not to invite you than to say It was so fortunate that I didn't have to put up with your company. For just this reason, the construction may occasionally be used to good effect in more formal contexts to invite the reader to take the point of view of the speaker or subject: The request seemed to her to be quite reasonable; it was so unfair of the manager to refuse. · New England speakers often use a negative form such as so didn't where others would use the positive so did, as in Sophie ate all her strawberries and so didn't Amelia. Since this usage may confuse a speaker who has not previously encountered it, it is best avoided in writing.

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.