fifth

n. & adj.
—n.
1 the position in a sequence corresponding to that of the number 5 in the sequence 1-5.
2 something occupying this position.
3 the fifth person etc. in a race or competition.
4 any of five equal parts of a thing.
5 Mus. a an interval or chord spanning five consecutive notes in the diatonic scale (e.g. C to G). b a note separated from another by this interval.
6 US colloq. a a fifth of a gallon of liquor. b a bottle containing this.
—adj. that is the fifth.
Phrases and idioms:
fifth column a group working for an enemy within a country at war etc. (from General Mola's reference to such support in besieged Madrid in 1936). fifth-columnist a member of a fifth column; a traitor or spy. Fifth Monarchy the last of the five great kingdoms predicted in Daniel 2:44. Fifth-monarchy-man hist. a 17th-c. zealot expecting the immediate second coming of Christ and repudiating all other government. fifth part = sense
3 of n.
fifth wheel
1 an extra wheel of a coach.
2 a superfluous person or thing.
3 a horizontal turntable over the front axle of a carriage as an extra support to prevent its tipping. take the fifth (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.
Derivatives:
fifthly adv.
Etymology: earlier and dial. fift f. OE fifta f. Gmc, assim. to FOURTH