copus

Perhaps from hippocras.

copus (plural copuses) (Britain, slang, obsolete, Cambridge University)

1. A mug.
   • 1835, Richard Gooch, Oxford and Cambridge Nuts to Crack (page 25)

     PORSON, Whose very name conjures up the spirits of ten thousand wits, holding both sides, over a copus of Trinity ale and a classical pun, would not only frequently “steal a few hours from the night,” but see out both lights and liquids, and seem none the worse for the carouse.

2. A drink of ale mixed with spices, and varied by spirits, wines, etc.
   • 1855, Thomas Gray, ‎William Mason, ‎John Mitford, The Correspondence of Thomas Gray and William Mason (page 352)

     We beg you would not stand fiddling about it, but be married forthwith, and then take chaise, and come […] all the way to Cambridge […] for our copuses and Welsh rabbits are impatient for you.

• (spiced drink): 1873, John Camden Hotten, The Slang Dictionary
• 1950, Morris Marples, University Slang