To endow is to furnish, but not with furniture. If you've been endowed with something, it means you've been given a gift — most likely a gift that can't be returned or exchanged, like a sense of humor or athletic ability or trust.
We usually use endow to refer to an ability or a quality, but you can endow someone with money, too. Endow is related to the word dowry, which is a gift that a man -– or sometimes a woman -– receives from his or her fiancé’s family before the wedding. The practice of giving dowries has fallen out of fashion in most Western countries, but there are still many parts of the world where it's common for the bride's family to provide the groom with an endowment of land and livestock.