votum

Votum, voti, n. Second declension neuter, the participle of voveo, vovere, vovi, votum, to vow. A votum is first the promise made to a god on conditional terms, do this for me and I will do that for you, and then by extension the thing prayed for and the wish itself.

The verb for keeping it is solvere, to loosen or discharge, not facere: votum solvere. That phrase is carved on thousands of altar stones as V.S.L.M., votum solvit libens merito, "he paid his vow willingly and deservedly". Note that ex voto means "in accordance with the vow" and so "as one wished"; it does not mean out of it. Gives vote, votive and devout.