U

incunabula

plural noun, singular in·cu·nab·u·lum [in-kyoo–nab-yuh-luh m, ing-] /ˌɪn kyʊˈnæb yə ləm, ˌɪŋ-/.

extant copies of books produced in the earliest stages (before 1501) of printing from movable type.
the earliest stages or first traces of anything.

pl n singular -lum (-ləm)

any book printed before 1501
the infancy or earliest stages of something; beginnings

“swaddling clothes,” also, figuratively, “childhood, beginnings;” 1824, from Latin incunabula (neuter plural), ultimately from cunae “cradle,” from PIE *koi-na-, from root *kei- “to lie; bed, couch.”