upāsaka, 優婆娑柯; 優波娑迦; 鄔波塞 (鄔波塞伽); 鄔波索迦 (or 鄔波素迦); 伊蒲塞. Originally meaning a servant, one of low caste, it became the name for a Buddhist layman who engages to observe the first five commandments, a follower, disciple, devotee.