Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
two-year is an adjective meaning "having a life cycle lasting two seasons". It carries one recorded sense.
having a life cycle lasting two seasons
“a biennial life cycle”
“parsnips and carrots are biennial plants often grown as annuals”
botany
Definitions, synonyms and semantic relations for two-year come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.