birthnight

From birth +‎ night.

birthnight (plural birthnights)

1. The night of someone's birth.
2. The night of someone's birthday.
   • 1671, John Milton, “The Fourth Book”, in Paradise Regain’d. A Poem. In IV Books. To which is Added, Samson Agonistes, London: […] J[ohn] M[acock] for John Starkey […], →OCLC, pages 104–105, lines 502–503:

     And of the Angelic Song in Bethlehem field, / On thy birth-night, that ſung thee Saviour born.

   • 2018, Norman Ross, Pater Noster in Condoland:

     he was on his way home and was going to take her out to IHOP for a late night birthday. I guess the best thing to have done, had I known , would have been to wish her a Happy Birthnight.

• “birthnight”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.