Definition of supernaculum in US English:

supernaculum

noun

slang
  • A drink to be consumed to the last drop; a wine of the highest quality. Frequently (and in earliest use) figurative: anything excellent of its kind. Now rare.

Origin

Late 16th century (in an earlier sense). Apparently humorously from classical Latin super + nagulum, naculum, Latinized form of German Nagel, after German auf den Nagel on to the nail.