Itadakimasu

いただきます。

Itadakimasu basically mean, "I will receive it." It is a very polite expression used when someone offers you something or gives you something. You would say it to someone high above you in social status. It is the keigo (honorific) form of "moraimasu." It is also what one says before starting to eat. In this case, it means, "I am about to receive this meal."

This expression originally comes from the word "itadaki," which means the top of a mountain. It can also mean, "to be crowned with." In the olden days, if someone received something from a superior, he would bow his head and place his hands, palms-up, over his head in order to receive it.