a formal ceremony establishing honorary parenthood. ~Notes: 上契 is a very old practice. In ancient times or maybe still today, when a family has only one child for generations, a child may be 契’ed to a large family in order to benefit from the luck; or to a very poor family in order to avoid jealousy of gods; or just to maintain a good relationship between two families. Nowadays, the 上契 practice is perhaps common only in the entertainment circles mainly for the purpose of fostering mutual assistance among the actors and artistes. In classical literature, or today in gangs, 契 is a formal ceremony to swear fidelity, becoming sworn brothers. The relevant terms of address for father, mother, son and daughter are 契爺, 契媽, 契仔, 契女 respectively. In Cantonese, the same kinship terms are used by Christians, when godparents are appointed during the rite of baptism (契神).