word choice - Which is correct: "I loaned him some money" or " I lent him some money"?

My Webster's New world Dictionary does not contain the word "loaned" at all, but my Thesaurus does, and the word "lent" is the first synonym listed. My wife, who learned English as a second language and therefore often speaks it better than I do, insists "lent" is more correct than "loaned" as the past tense verb form. Which is more correct?