I've been seeing this everywhere. From (http://pubs.acs.org/doi/abs/10.1021/nl025785g) "In PbSe, the electron, hole, and exciton Bohr radii are 23, 23, and 46 nm, respectively. " 

Now I understand the concept of a de Broglie wavelength, but a Bohr radius I thought to be "The Bohr radius (a0 or rBohr) is a physical constant, approximately equal to the most probable distance between the proton and electron in a hydrogen atom in its ground state." 

How can an electron have a Bohr radius?