Half-caste and Half blood

Half-caste noun - An offensive term for the offspring of parents of different races or cultures.

Half blood and half-caste are semantically related In some cases you can replace phrase "Half blood" with "Half-caste", this phrases are similar.

Half blood noun - One of siblings who have only one parent in common.

Half-caste and half blood are semantically related in sibling sharing one parent topic. You can use "Half-caste" instead a noun phrase "Half blood".