Nomenclature is a method of naming used in all branches of Science. 

Hybridisation is a phenomenon of mixing of atomic orbitals of different energies, to form new and stable atomic orbitals with low energy. For example, s and p orbitals can combine in different numbers to give either sp, or sp2, or sp3 hybrid orbitals.

Valence bond theory was developed as a part of quantum mechanics to explain chemical bonding. It tells how the atomic orbitals of the dissociated atoms combine to give individual chemical bonds when a molecule is formed.