IPA: /ˈsɪŋɡlˌtriː/
KK: /ˈsɪŋɡlˌtri/
A singletree is a part of a harness used to connect a single horse to a vehicle or plow, allowing the horse to pull it.
The farmer attached the cart to the singletree before heading out to the fields.
Singletree → The word is formed from "single" (from Old English *singe*, meaning one or alone) and "tree" (from Old English *treow*, meaning a wooden structure or plant). A singletree refers to a single piece of wood used to connect a horse to a plow or cart, emphasizing its singular function in harnessing.
Think of 'one' ('single') piece of wood ('tree') that connects a horse to a cart — that's what a singletree does.