n. ~ 1. A print made using the Prussian blue (ferroprussiate) process; a cyanotype. – 2. A reproduction of an architectural drawing, especially one made using the blueprint process.
Notes
In general, 'blueprint' is used for architectural drawings, while cyanotype is used to describe continuous-tone photographic prints, even though the process is the same. It is not uncommon for 'blueprint' to be used generically to refer to any architectural drawings, regardless of process.