fifth

noun
The person or thing in the fifth position.One of five equal parts of a whole.The fifth gear of an engine.A quantity of liquor equal to one-fifth of a gallon, or, more commonly, 750 milliliters (that is, three quarters of a liter).The musical interval between one note and another seven semitones higher (the fifth note in the major/minor scale)The fifth voice in a polyphonic melody.

verb
To support something fifth, after four others have already done so.To divide by 5, equates to multiplying a denominator by 5

adjective
The ordinal form of the number five.