adverb
In half: in two equal parts, shares, etc.
adjective
Half and half.
Used to describe two possible outcomes as being equally likely.
noun
(sports) A challenge between two opposing players, where both have an equal chance of taking possession.
(skateboarding) Ellipsis of fifty-fifty grind, a rail or edge grind, using both trucks to grind along, longitudinally aligned.
(snowboarding) Ellipsis of fifty-fifty slide, a rail slide where the snowboard is longitudinally aligned with the direction of the slide, down the centerline.