C18: from Latin ad to + noun, formed on the model of adverb
adnoun in American English
(ˈædˌnaun)
noun
Grammar
an adjective used as a noun, as meek in Blessed are the meek; absolute adjective
Word origin
[1745–55; ad(jective) + noun]This word is first recorded in the period 1745–55. Other words that entered Englishat around the same time include: compressor, personification, pompadour, recapture, umbilical cord