Lewis Short
(verb) : a-stĭpŭlor (adst-, Weissenb., Jan), āri, 1, (
* Act.adstĭpŭlo, āre, Jul. Val. Rer Gest. Alex. M 1, 18), to join in a stipulation, to stipulate with, Gai Inst. 3, 112.— Trop, to agree with one, = adsentiri: adstipulari irato consuli,Liv. 39, 5: Hellanico adstipulatur Damastes memorans, etc.,Plin. 7, 48, 49, § 154.
Charlton T. Lewis, Charles Short, A Latin Dictionary