(1) (IDL On the Net) See IDL.

(2) An atom with fewer or greater electrons than normal as a result of a chemical reaction in the material. A positive ion, called a "cation" (pronounced "cat-eye-en"), is an atom that has one or more electrons stripped out, which means it has fewer electrons in its electron shells than it has protons in its nucleus. A negative ion, called an "anion" (pronounced "an-eye-en") is an atom that has one or more electrons forcibly added.

Batteries Contain Positive and Negative Ions
In a battery, there are positive ions on one side and negative ions on the other. When a conductor is placed in between to complete the circuit, the electrons flow from the negative ions to the positive side where they join the positive ions. See ion deposition.