One of four standard process colors. The blue color; Also known as process blue; Shade of blue; One of four basic ink colors used in four color printing process. 

Ink color used in addition to the four needed by four-color process.  

(1) Any color created by printing only one ink, as compared to a color created by printing four-color process. Also called block color and spot color. (2) Color that seems weak or lifeless.