half; semi-; partial
half-past
odd number
fourth rank; fourth class; fourth party (in a contract, etc.)
三時半に会おうかな。
Maybe we should meet at three thirty.
ケーキを半分にして食べた。
I cut the cake in half and ate it.
半年もかけてやっと完成させました。
It took half a year to finally complete it.