ˌ ̷ ̷ ̷ ̷ˈhedə(r) noun
Etymology: double head (from double (I) + head ) + -er
1. : a railroad train pulled by two locomotives
2.
a. : two games (as of baseball) played consecutively on the same day by the same teams
b. : two games (as of basketball) played consecutively on the same day by two different pairs of teams