as

adverb

  1. To such an extent or degree; to the same extent or degree.

    "It's not as well made, but it's twice as expensive."

  2. Considered to be, in relation to something else; in the relation (specified).

    "1865, The Act of Suicide as Distinct from the Crime of Self-Murder: A Sermon"

  3. For example; for instance. (Compare such as.)

preposition

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

    "They're big as houses."

  2. In the role of.

    "He was never seen as the boss, but rather as a friend."

conjunction

  1. In the (same) way or manner that; to the (same) degree that.

    "As you wish, my lord!"

  2. At the time that; during the time when:

  3. Being that, considering that, because, since.

    "As it’s too late, I quit."

  4. Introducing a comparison with a hypothetical state (+ subjunctive, or with the verb elided): as though, as if.

  5. Functioning as a relative conjunction, and sometimes like a relative pronoun: that, which, who. (See usage notes.)

    "He had the same problem as she did getting the lock open."

  6. (possibly obsolete) Than.

Synonyms: while, whilst, given that, seeing that, albeit, although

noun

  1. (unit of weight) A libra.

  2. Any of several coins of Rome, coined in bronze or later copper; or the equivalent value.