fifty-fifty

Short definition from Wiktionary

Adverb

1. 1
   In half: in two equal parts, shares, etc.

Adjective

1. 1
   Half and half.
2. 2
   Used to describe two possible outcomes as being equally likely.

Noun

1. 1
   A challenge between two opposing players, where both have an equal chance of taking possession.
2. 2
   Ellipsis of fifty-fifty grind, a rail or edge grind, using both trucks to grind along, longitudinally aligned.
3. 3
   Ellipsis of fifty-fifty slide, a rail slide where the snowboard is longitudinally aligned with the direction of the slide, down the centerline.