- ammoniaA gaseous, toxic compound of hydrogen and nitrogen, NH₃, with a pungent smell and taste.
- AmmonAn ancient nation occupying the east of the Jordan River, between the torrent valleys of Arnon and Jabbok, in present-day Jordan.
- AmunAn Egyptian wind deity associated with the town of Thebes; later (post-16th century BCE) the creator deity, often depicted with curling ram horns.
- sal ammoniacA rare mineral composed of ammonium chloride found around volcanic fumaroles and guano deposits.