From Longman Dictionary of Contemporary Englishsixthsixth1 /sɪksθ/ ●●● S3 W3 adjective HMPARTcoming after five other things in a series her sixth birthday the sixth century —sixth pronoun Let’s have dinner on the sixth (=the sixth day of the month).
Examples from the Corpus
sixth• June is the sixth month.the sixth• I'll call you on the sixth.sixthsixth2 noun [countable] HMPARTone of six equal parts of something About one sixth of the children admitted to taking drugs. 