as (Noun) — A very poisonous metallic element that has three allotropic forms; arsenic and arsenic compounds are used as herbicides and insecticides and in various alloys; found in arsenopyrite and orpiment and realgar.
as (Noun) — A United States territory on the eastern part of the island of Samoa.
as (Noun) — The 1st letter of the Roman alphabet.
as (Adverb) — To the same degree. ex. "birds were singing and the child sang as sweetly" ex. "sang as sweetly as a nightingale" ex. "he is every bit as mean as she is"
as (Adverb) — In the idea, character, or condition of, limiting the view to certain attributes or relations. ex. "dressed up as a ghost"
as (Conjunction) — For the reason that; on account of. ex. "empty, as it had been upside down"
as (Conjunction) — At the same time that. ex. "they were walking home as they were discussing the problem"