[Gr. basis, base]

1. The lower part of anything; the supporting part.
2. The principal substance in a mixture.
3. Any substance that combines with hydrogen ions (protons); a hydrogen ion acceptor (Bronsted base).
Strong bases (such as sodium hydroxide or lye) are corrosive to human tissues. Whether an unknown chemical compound is a base or an acid may be determined by the color produced when it is added to a solution containing an indicator.
SYN: alkali
See: acid; pH
4. A substance that can donate a pair of electrons (Lewis base).

Subentries:
cavity base
denture base
nucleic base