Depending on the position of an atom on a surface, it can be referred to by one of several names.  Figure 1 illustrates the names for the atomic positions and point defects on a surface for a simple cubic lattice.
Figure 2 shows a scanning tunneling microscopy topographic image of a step edge that shows many of the features in Figure 1.<br>Figure 3 shows a crystal surface with steps, kinks, adatoms, and vacancies in a closely packed crystalline material, which resembles the surface featured in Figure 2.