Webster's Revised Unabridged Dictionary · 1913

Whippletree

Whippletree , noun

[See Whip, and compare Whiffletree.]

1.
The pivoted or swinging bar to which the traces, or tugs, of a harness are fastened, and by which a carriage, a plow, or other implement or vehicle, is drawn; a whiffletree; a swingletree; a singletree. See Singletree.
[People] cut their own whippletree in the woodlot. — Emerson
2.
(Botany) The cornel tree. — Chaucer