arroba

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A unit of weight formerly used in Spanish-speaking countries, equal to about 11.3 kilograms (25 pounds).
• noun A unit of weight formerly used in Portuguese-speaking countries, equal to about 14.4 kilograms (32 pounds).
• noun A liquid measure formerly used in Spanish-speaking countries, having varying value but equal to about 16.2 liters (17 quarts) when used to measure wine.

from The Century Dictionary.

• noun A Spanish and Portuguese unit of weight.
• noun A measure for wine, spirits, and oil in Spanish countries, arising from the Moorish practice of weighing those liquids; the cantara.

from the GNU version of the Collaborative International Dictionary of English.

• noun 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.
• noun A Spanish liquid measure for wine = 3.54 imp. gallons, and for oil = 2.78 imp. gallons.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun An old Spanish weight used in Mexico and South America, approximately 25.36 pounds avoirdupois.
• noun An old Portuguese weight used in Brazil, approximately 32.38 pounds avoirdupois.
• noun An old Spanish liquid measure, approximately 3.54 imperial gallons (for wine) or 2.78 imperial gallons (for oil).

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a liquid measure (with different values) used in some Spanish speaking countries
• noun a unit of weight used in some Spanish speaking countries