The labeling is s p_y p_z p_x d_{xy} d_{yz} d_{z2-r2} d_{xz} d_{x2-y2}, with eventually more columns if the spin and/or the spin-orbit effects are taken into account. These kind of questions can be easily answered by taking a look at the VASP wiki: https://www.vasp.at/wiki/index.php/DOSCAR
Note that the orbital populations are not rotational invariants, i.e., the population of a particular orbital will depend on the orientation of the system within the unit cell defined in the POSCAR, so be careful about the interpretation of these values.