What is the difference between an anion and a cation?

Answer 1

An anion has a negative electric charge and a cation has a positive electric charge. This is the fundamental distinction, but the chemistry of each type is generally different also: Very few chemical structures, except for single atoms in high vacuum, can be or become both cations and anions.

Answer 2

An anion is a negatively charged ion that gains electrons, while a cation is a positively charged ion that loses electrons. Anions are formed when atoms gain electrons to achieve a stable electron configuration, while cations are formed when atoms lose electrons.