aha! come now! come on! (expressing delight, playful remonstrance, encouragement)
References
“eia”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
“eia”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
eia in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.
eia in Charles du Fresne du Cange’s Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
Allen and Greenough's New Latin Grammar for schools and colleges founded on comparative grammar, edited by J. B. Greenough, G. L. Kittredge, A. A. Howard, Benj. L. D'Ooge, p. 139: "The following list comprises most of the Interjections in common use:— [...] êia [...]"