A<unk>  <unk>  is, as its name would indicate, a receptor which binds<unk><unk>  factors (TNF).
Because "TNF" is often used to describe TNF alpha, "TNFR" is often used to describe the receptors that bind to TNF alpha - namely, CD120. However, there several other members of this family that bind to the other TNFs.
Tumor necrosis factor receptor
Interleukin-8 receptor
Fibroblast growth factor receptor
Pattern recognition receptor
Receptor tyrosine kinase
Cell adhesion molecule
Soluble CD40 ligand 
T cell receptor