Definition of doubletree in English:

doubletree

noun

North American
  • A crossbar in front of a wagon with a swingletree at each end, enabling two horses to be harnessed.

    ‘The doubletree on the wagon could be adjusted to allow one horse to pull more.’
    ‘The wheel horses pull on the doubletree against this hammerpin running through the wagon-tonque.’

Origin

Mid 19th century from double, on the pattern of singletree.

Pronunciation

doubletree

/ˈdʌb(ə)ltriː/