noun
(sports) A pair of games played one after another between the same teams.
A pair of sporting events, one after the other, at a single venue.
A pair of sporting events, one after the other, broadcast on the same television channel.
(fishing) The catching of a single fish simultaneously by two fishermen when fishing together.
(numismatics) A double-headed coin.
(rail transport) A train pulled by two locomotives.
(slang) Double penetration