half-

From Middle English half-, from Old English healf-, from Proto-Germanic *halba- (“half-”), from *halbaz (“half”). Cognate with Dutch half- (“half-”), German halb- (“half-”), Swedish halv- (“half-”), Icelandic hálf- (“half-”). More at half.

half-

1. half or partial; not complete
2. Used before brother, sister, uncle, aunt, and so forth, to indicate that the person being identified is related only through one parent, grandparent, and so forth, rather than two.

Can be used to describe an exact half like in half-filled or half-price but can also be used in a more loose sense, for example half-awake/half-asleep (awake but not fully alert) or half-decent (somewhat less than decent).

• quarter- (prefix for a fourth part)