What is the meaning of hybridization of atomic orbitals?

(N/A) To explain the characteristic geometric shapes of polyatomic molecules like $CH_4$,$NH_3$,and $H_2O$,Pauling introduced the concept of hybridization of atomic orbitals.
Pauling's definition: According to him,atomic orbitals combine to form a set of equivalent orbitals,which are known as 'hybrid orbitals'.
These hybrid orbitals are used in bond formation instead of pure atomic orbitals. The process of forming a new set of orbitals with equal energy and identical shape is called 'hybridization'.
Example: One $2s$ and three $2p$ orbitals of carbon mix and hybridize to form four new equivalent $sp^3$ hybrid orbitals of identical shape.