incitabulum

From incitō (“to incite; to stimulate”) + -bulum.

incitābulum n (genitive incitābulī); second declension

1. incentive, stimulus

Second-declension noun (neuter).

• “incitabulum”, in Charlton T. Lewis and Charles Short (1879), A Latin Dictionary, Oxford: Clarendon Press
• "incitabulum", in Charles du Fresne du Cange, Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)