ETYM as. healf, half, half; as a noun, half, side, part; akin to os., OFries., and Dutch half, German halb, Swed. half, Dan. halv, Icel. hâlfr, Goth. halbs. Related to Halve, Behalf.
(Of siblings) Related through one parent only.
1. Consisting of one of two equivalent parts in value or quantity.
2. Partial.

ETYM as. healf. Related to Half.
(Irregular plural: halves).
In various games or performances: either of two periods of play separated by an interval.

1. The position of a back on a football team.
2. (Football) The person who plays halfback; SYN. running back.