Source : Webster's Revised Unabridged Dictionary (1913)

Rummer \Rum"mer\, n. [D. roemer, romer, akin to G. r["o]mer, Sw.
   remmare; perhaps properly, Roman.]
   A large and tall glass, or drinking cup. [Obs.] --J. Philips.

Source : WordNet®

rummer
     n : a large drinking glass (ovoid bowl on a stem) for drinking
         toasts