Fibronectin is a large glycoprotein found in plasma (plasma fibronectin) and the extracellular matrix (cellular fibronectin). The former type was initially named cold-insoluble globulin (Morrison et al. 1948). In the 1970s, several laboratories independently characterized cellular fibronectin, naming it surface glycoprotein antigen (Vaheri and Ruoslahti 1974), large external transformation sensitive protein (LETS) (Hynes and Bye 1974), and cell surface protein (Yamada and Weston 1974), among others. When the common identity of these proteins was recognized, the name fibronectin (from the Latin fibra, meaning “fiber” and nectere meaning “to bind”) was adopted.