A compound must be a molecule (WRONG)?

This was a test question of mine and they said that a compound must be a molecule. This is incorrect in my opinion. For example, NaCl is an ionic compound made up of Na+ cations and Cl- anions that form a crystal lattice in solid phase. They are not molecules. Can expert chemists back me up because I see a lot of information that supports my claim. I thought molecules arise from covalent bonding.