• (n.) A work of art or of human industry, of an early epoch; especially, a book printed before a. d. 1500.
In`cu·nab'u·lum noun ; plural Incunabula . [ Latin incunabula cradle, birthplace, origin. See 1st In- , and Cunabula .] A work of art or of human industry, of an early epoch; especially, a book printed before a.d. 1500. 
early printed book; early version of a thing