Itadakimasu is a traditional phrase said before eating a meal. It literally means "I humbly receive." It's an expression of gratitude for the food, the people who prepared it, and all living things that contributed to the meal. You say it with your hands together. For example, "いただきます！" (Let's eat!).

食事(しょくじ)を始(はじ)める前(まえ)に言(い)う感謝(かんしゃ)の言葉(ことば)です。命(いのち)や作(つく)ってくれた人(ひと)に感謝(かんしゃ)します。「いただきます！」