What is the name given to an impurity atom that adds holes to a semiconductor crystal structure?

In semiconductor physics, doping is the process of adding specific impurity atoms to a pure crystal lattice to change its electrical properties. When an impurity atom has fewer valence electrons than the semiconductor atoms (such as boron added to silicon), it creates a missing electron in the crystal structure, known as a 'hole'. Because this hole can easily 'accept' an electron from a neighboring atom to complete the bond, this type of impurity is called an acceptor impurity. The presence of these holes makes the material 'P-type' (positive). Conversely, a 'donor' impurity has extra valence electrons and donates them to the crystal, creating 'N-type' (negative) material. Remembering that acceptors accept electrons (leaving holes) helps distinguish the two.