The name Crk is from "CT10 Regulator of Kinase" where CT10 is the avian virus from which was isolated a protein, lacking kinase domains, but capable of stimulating phosphorylation of tyrosines in cells.
Crk's name is derived from the acronym "CT10 Regulator of Kinase," which refers to a viral source (CT10) that led to the discovery of a protein lacking kinase capabilities but capable of activating tyrosine phosphorylation in cells.