AS

adverb

1. To such an extent or degree; to the same extent or degree.
2. Considered to be, in relation to something else; in the relation (specified).
3. For example; for instance. (Compare such as.)

preposition

1. Introducing a basis of comparison, with an object in the objective case.
2. In the role of.

conjunction

1. In the (same) way or manner that; to the (same) degree that.
2. At the time that; during the time when:
3. Being that, considering that, because, since.