Congius
Part of speech: noun
Definition: An ancient Roman liquid measure, being six sextarii or one eighth of an amphora; also used as a weight measure during the reign of Vespasian, being the weight of that volume of water.
Gallon
Part of speech: noun
Definition: A unit of volume, equivalent to eight pints or(in plural gallons; colloquial) A large quantity (of any liquid).
Example sentence: Scientists at MIT and engineering schools all across America say that they could improve the fuel economy standards for the existing set of vehicles by 10 miles per gallon using existing technology, without compromising safety or comfort at all.