Why do they call it a fifth?!
Answers: Where does this slang term come from? I have always wondered, even though I use the term all the time.
It is one-fifth of a gallon.
a 1/5th of a quart
I believe because it is four fifths of a gallon.
A 'fifth' is 750ml, 25.4 Oz., approx. 1/5 of a gallon.
It used to be 1/5 of a gallon, but liquor is now converted to metric when sold so now a "fifth" is actually 750 mL. Strange I know.
750 mL is roughly a fifth of a gallon, which is the size the bottles used to be before conversion to the metric system.
A fifth refers to the size of the bottle. A fifth is 1/5 of a gallon.
Since there is 128 ounces in a gallon, a fifth would be 25.6 ounce bottle.
Prior to metric conversion, liquor was sold in bottles that contained 4/5's of a quart, or 1/5 of a gallon, hence the nickname.