ax·le·tree 
(ăksəl-trē′)
(ăksəl-trē′)n.
A crossbar or rod supporting a vehicle, such as a cart, that has terminal spindles on which the wheels revolve.
[Blend of Middle English axel, axle; see AXLE, and Middle English axtre, axletree (ax from Old English eax + tre, tree; see TREE).]