Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
4th is an adjective meaning "coming next after the third and just before the fifth in position or time or degree or magnitude". It carries one recorded sense.
coming next after the third and just before the fifth in position or time or degree or magnitude
“the quaternary period of geologic time extends from the end of the tertiary period to the present”
Definitions, synonyms and semantic relations for 4th come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.