If a molecule is "an electrically neutral group of two or more atoms held together by chemical bonds" then why aren't two ions held in an ionic bond, a molecule, since an ionic compound is electrically neutral?

@barlop On contrary. You can have for example NaCl molecules, but in gas phase.

Solid NaCl can be viewed as one big molecule, much like any 3D lattice.

Ionic bonds are chemical bonds because they aren't completely ionic. Otherwise there's no chemical bond, just two separate ions.