Unit vectors, a,b,c
Index
Unit vectors are the fundamental translation vectors in a crystal lattice that define the edges of the unit cell. The diagram shows a general unit cell that can be characterized by the three non-coplanar unit vectors:
a, b, c, that are selected such that a < b < c, and the three angles a, b, g.

                                 From: Callister, "Materials Science and Engineering," Wiley (1994)