constituting number five in a sequence; 5th:the fifth century bcher mother had just given birth to another child, her fifththe world’s fifth-largest oil exporterthe fifth of November
(a fifth/one fifth) each of five equal parts into which something is or may be divided.
the fifth finisher or position in a race or competition:he finished fifth
(in some vehicles) the fifth (and typically highest) in a sequence of gears:in my panic I changed from third to fifth
fifthly (used to introduce a fifth point or reason):fourth, it can aid the process of life review, and fifth, it is an enjoyable and stimulating experience
Music an interval spanning five consecutive notes in a diatonic scale, in particular (also perfect fifth) an interval of three whole steps and a half step (e.g., C to G):strings tuned a fifth apart
Music the note which is higher by a fifth than the root of a diatonic scale.
(a fifth of) US informal a fifth of a gallon, as a measure of liquor, or a bottle of this capacity:a fifth of whiskey
the fifth grade of a school.
Phrases
take (or plead) the Fifth (Amendment)
(in the US) exercise the right guaranteed by the Fifth Amendment to the Constitution of refusing to answer questions in order to avoid incriminating oneself.