TKG English Learner's Dictionary

as

2 entries: preposition · conjunction

aspreposition

American /æz/ British /æz/ also /əz/ the weak, unstressed form heard in ordinary speech
very commondefining vocabulary

  1. in a role or statein the position, job, role, or state of someone or something

    Often placed at the start of a sentence and followed by a comma, especially to name a stage of life or a role held at a particular time: As a child, she loved to draw; as president, he made several changes.

    Collocations

    verb + preposition work as, serve as, act as, know someone as, use something as

    Compare like (as names someone's actual role or job; like only compares to it: he works as a doctor (he is one) against he works like a doctor (he behaves similarly)); than

Usage

As is also a conjunction, joining two clauses (as I was leaving, the phone rang), and part of the comparison pattern as ... as (as tall as her brother); this entry covers only the preposition, used directly before a noun phrase.

Common mistakes

He works like a doctor at the clinic. He works as a doctor at the clinic.
As names someone's actual job; like only says something resembles it, without being it.

See also as

asconjunction

American /æz/ British /æz/ also /əz/ the weak form, used in the middle of a sentence in ordinary speech Usually said weakly, like uz, in the middle of a sentence. The full form, which rhymes with jazz, is used when the word is stressed.
very commondefining vocabulary

As joins two clauses to say that things happen at the same time, to the same degree, for a reason, or in the same way.

  1. at the same timeduring the time that, or at the moment when, something happens

    Often used for a short action that happens during a longer one, or for two actions that happen together. Just as means at exactly the moment when.

    Compare while (while is used for two longer actions at the same time; as also works for a short action inside a longer one); when

    1. aused to show that one thing changes at the same time as another

  2. comparingused to introduce the second part of a comparison that shows two things are equal or the same

    In as ... as, an adjective or adverb in its plain form goes between the two words (as big as, as quickly as); the second as introduces the thing compared. After it, formal English uses a clause (as tall as I am); everyday English often uses an object pronoun (as tall as me). A negative can use not so ... as, but not as ... as is more common.

    Collocations

    phrase as ... as, not as ... as, the same ... as, as much as, as far as

    Compare than (than follows a comparative form (taller than); as follows as and a plain adjective (as tall as))

  3. becausebecause; for the reason that

    Gives a reason that the listener probably knows already or will easily accept, and often comes at the start of the sentence. It is a little formal; in everyday American speech because and since are more common. When as could also mean while, use because or since to be clear.

    Synonyms because

    Compare because (because puts more weight on the reason and is the usual answer to why); since

  4. in the way thatin the way that, or in the same way that

    Collocations

    phrase as I said, as you know, as usual, as expected, as it is

    Compare like (in informal speech, like is often used before a clause in place of as (like I said); as is the form for careful writing)

    1. aused before a short clause that connects what is said to what someone knows, says, or has said

  5. althoughdespite the fact that

    Used only after an adjective, an adverb, or a verb that comes first in the clause: tired as she was means although she was tired.

    formal

Choosing between because · since · as

Because is the usual word for a reason, especially a new or important one, and the only one of the three that answers why: We left because the music was too loud. Since and as give a reason the listener already knows or will accept, and usually come first: Since you're busy, I'll call later; As it's late, let's stop here. As is the most formal of the three and can be mistaken for while, so it is rarer in speech.

Usage

As directly before a noun phrase (She works as a nurse) is a preposition and has its own entry. In as ... as (as tall as), the first as is an adverb and the second is the conjunction described here. As if, as though, as long as, and as soon as have their own entries.

Common mistakes

She is as tall than her brother. She is as tall as her brother.
After as and an adjective, the comparison continues with as, not than.
I have the same bag like you. I have the same bag as you.
The same is followed by as.
This room is as bigger as that one. This room is as big as that one.
Use the plain form of the adjective between as and as.

See also as (before a noun phrase: as a nurse); as (the first as in as tall as); as if

For translators

Meaning across languages As can mean while, because, in the way that, or although, and most languages need a different word for each. Read the whole sentence: As she was leaving is about time; As she was tired gives a reason.
Grammar trap Between as and as, an adjective or adverb stays in its plain form: as big as, never as bigger as or as more big as.