preposition used to describe sb/sth appearing to be sb/sth else: They were all dressed as clowns. ◆ The bomb was disguised as a package. used to describe the fact that sb/sth has a particular job or function: She works as a courier. ◆ Treat me as a friend. ◆ I respect him as a doctor. ◆ You can use that glass as a vase. ◆ The news came as a shock. ◆ She had been there often as a child (= when she was a child).
adverb as ...as ... used when you are comparing two people or things, or two situations: You're as tall as your father. ◆ He was as white as a sheet. ◆ She doesn't play as well as her sister. ◆ I haven't known him as long as you (= as you have known him). ◆ He doesn't earn as much as me. ◆ He doesn't earn as much as I do. ◆ It's not as hard as I thought. ◆ Run as fast as you can. ◆ We'd like it as soon as possible. used to say that sth happens in the same way: As always, he said little. ◆ The 'h' in honest is silent, as in 'hour'.
conjunction while sth else is happening: He sat watching her as she got ready. ◆ As she grew older she gained in confidence. in the way in which: They did as I had asked. ◆ Leave the papers as they are. ◆ She lost it, just as I said she would. used to state the reason for sth: As you were out, I left a message. ◆ She may need some help as she's new. used to make a comment or to add information about what you have just said: As you know, Julia is leaving soon. ◆ She's very tall, as is her mother. (written) used to say that in spite of sth being true, what follows is also true