An amphiprotic substance can act as both a proton donor (acid) and a proton acceptor (base) depending on the chemical environment. Water is a common example of an amphiprotic substance.
Brรธnsted-Lowry Acid: A species that donates a proton (H+) in a chemical reaction.
Brรธnsted-Lowry Base: A species that accepts a proton (H+) in a chemical reaction.
Amphoteric: A broader term for substances that can react with both acids and bases, not limited to just transferring protons.