arroba

from WordNet (r) 3.0 (2006)

arroba
    n 1: a unit of weight used in some Spanish speaking countries
    2: a liquid measure (with different values) used in some Spanish
       speaking countries

from The Collaborative International Dictionary of English v.0.48

Arroba \Ar*ro"ba\, n. [Sp. and Pg., from Ar. arrub, ar-rubu, a
   fourth part.]
   1. A Spanish weight used in Mexico and South America = 25.36
      lbs. avoir.; also, an old Portuguese weight, used in
      Brazil = 32.38 lbs. avoir.
      [1913 Webster]

   2. A Spanish liquid measure for wine = 3.54 imp. gallons, and
      for oil = 2.78 imp. gallons.
      [1913 Webster]