Onti is a unit of silver. Alma names “an onti of silver” with a senum, amnor, and ezrom of silver (Alma 11:6). An onti “was as great as them all” (Alma 11:13).
Zeezrom showed Amulek “six onties of silver” and offered them if Amulek would deny the existence of a Supreme Being (Alma 11:22). Amulek called the six onties “of great worth” and said Zeezrom had desired that he deny “the true and living God” (Alma 11:25).