›[C, U]one of two equal parts of something; 12;: Rice is eaten by half of the world's population.Cut the lemons into halves.It'll take half an hour to get there.Jenny lived in Beijing for a year and a half.
break/cut/split sth in half›to divide something into two equal parts: Divide the dough in half and roll it out into two circles.
decrease/increase, etc sth by half›to make something smaller/larger, etc by half its size: The drug reduces the risk of stroke by half.
half past one/two/three, etcmainly UK›30 minutes past one o'clock/two o'clock/three o'clock, etc: We got back to our hotel at half past seven.
half one/two/three, etcUKinformal›30 minutes past one o'clock/two o'clock/three o'clock, etc: "What time does it start?" "About half six."