「お茶」 (ocha) means "tea," often specifically "green tea" in Japan. It's a popular beverage made by infusing tea leaves in hot water. You use 「お茶」 when offering or requesting tea. 「日本人はよくお茶を飲みます。」 (Japanese people often drink tea.)

日本(にほん)で特(とく)に一般的(いっぱんてき)な、茶葉(ちゃば)を煮出(にだ)した飲(の)み物(もの)です。緑茶(りょくちゃ)を指(さ)すことが多(おお)いです。