jump-off

[juhmp-awf, -of] /ˈdʒʌmpˌɔf, -ˌɒf/
noun
1.
a place for jumping off.
2.
a point of departure, as of a race or a military attack.
3.
the start of such a departure.
4.
a supplementary contest among horses tied for first place in a jumping contest.
Origin
1870-75, Americanism; noun use of verb phrase
British Dictionary definitions for jump-off

jump-off

noun
1.
an extra round in a showjumping contest when two or more horses are equal first, the fastest round deciding the winner
verb
2.
(intransitive, adverb) to begin or engage in a jump-off