As

adverb
 * 1) used in comparisons to refer to the extent or degree of something.

"go as fast as you can" conjunction
 * 1.

used to indicate that something happens during the time when something is taking place.

"Frank watched him as he ambled through the crowd"

Similar:

while

just as

even as

at the (same) time that

at the moment that

during the time that

just when

simultaneously
 * 2.

used to indicate by comparison the way that something happens or is done.

"they can do as they wish"

Similar:

in the (same) way that

the (same) way

in the (same) manner that

like preposition
 * 1.

used to refer to the function or character that someone or something has.

"it came as a shock"

Similar:

in the guise of

with the appearance of

in the character of

so as to appear to be

in the role of

being

acting as

functioning as
 * 2.

during the time of being (the thing specified).

"he had often been sick as a child"