For questions about chemical bonds (ionic/covalent/etc.), their properties (length, energy, angle, etc.) or their relation to other molecular properties (intermolecular forces/dipole moment/etc.). Do not confuse this tag with [lewis-structures], [dipole], [intermolecular-forces], etc.
A chemical bond is an interaction between atoms, which results in the release of energy when created. The same can be told about intermolecular interactions, but they are usually weaker and, perhaps more importantly, their covalent component is low to none. Ionic component is complementing to covalent, and can be attributed even to symmetric diatomic molecules, but without at least minuscule covalent character, the bond would be rather intermolecular interaction.
It is one of the most fundamental concepts of chemistry, along with chemical reactions, which result in bonds being broken and/or formed.