what is full name of t2g nd eg

In the Crystal Field Theory, when the splitting of the d-orbital occurs, it gets divided into two parts... The upper part with higher Energy is the t2g and the lower part with lower Energy is called the eg.
There is no full name of such orbital and it has been denoted to give the energy value

The letters say how many orbitals of same symmetry are combined.Two orbitals you call (e)Three orbitals you call (t)If you have 2 sets of 3 orbitals then one is called t1 and the other as t2. The g stands for gerade (german) means even. Like an even function the orbital remains the same after inversion.

According MOT, in octahedral complex 9atomic orbital divided into four symmetrical classes. A1g,T1u,Eg and T2g.1 and 2 show multiplicity. g is gerade and u is a ungerad. A is singly degenerate, E is doubly degenerate, T is triple degenerate

In splitting the t2g eg t1u ag where t stand for triple degenerate orbital and e stand for double degenerate orbital a stand for spherical means on degeneracy where 1 stand for single degeneracy in each orbital 2 for double degeneracy in each orbital example in p orbitals each have single degeneracy denoted as 1 and d orbital of t2g level have double degeneracy g is used for shape having centre of symmetry and u is used for shape having plane of symmetry