Used as a noun or adverb to indicate exactly one half of something, or a partial amount. Very common in everyday speech.
ケーキを半分に切ってください。
Please cut the cake in half.
Only half of the work is done yet.
I cut the apple in half and gave a piece to my little brother.
We split the pizza in half and ate it.
Half of the participants were women.
I've finished more than half of my homework.
半分 means simply 'half' of any quantity, while 半値 specifically refers to half of a price or value, not a general half.
半分 means simply 'half' of a single thing, whereas 半々 describes a ratio in which two parts are equal to each other.
半分 simply means 'half' as a fraction or quantity, whereas 中途半端 describes an unsatisfactory, incomplete way of doing or being something.
half joking; half in jest
half in jest; partly for fun; capricious