Ionic Bonding (also called ion-ion attraction) is the attraction between a positive ion and an negative ion. That's it. Nothing else. Seriously, that all there is to say.
Alternate version with WAY too much information
Many other resources will tell you a long story about ionic bonding that goes something like this:
A chlorine atom and a sodium atom meet. The chlorine atom pulls on the outermost electron of the sodium and pulls so hard that it completely removes the electron from the sodium. As a result the chlorine becomes a chloride ion (with a negative 1 charge) and the sodium atom becomes a sodium ion (with a positive 1 charge). The two oppositely charged ions then attract each other.
This is a nice story and it may happen lots of times, but the story is just that, a story. Only the last sentence has anything to do with ionic bonding. The rest may explain how the chlorine and sodium became ions, but it also may NOT be how they became ions. In the end, it doesn't matter HOW the two became ions, only that they did and that they now attract each other.