Ancestor worship (拜祖), also ancestor veneration (敬祖), is a religious practice based on the belief that one's ancestors possess supernatural powers. All cultures attach ritual significance to the passing of loved ones, but this is not equivalent to ancestor worship. Rather, ancestor worship involves the same sort of religious practices one sees when people appease or supplicate other entities thought to exist and possess supernatural powers, such as gods, angels, saints, or demons. While far from universal, ancestor worship or ancestor veneration occurs in societies with every degree of social, political, and technological complexity, and it remains an important component of various religious practices in modern times.
Ancestor worship in some cultures (such as Chinese) seeks to honor the deeds, memories, and sacrifice of the deceased. Much of the worship includes visiting the deceased at their graves, making offerings to the deceased to provide for their welfare in the afterlife. For instance, a toothbrush, comb, towel, slippers, and water are provided by the coffin so that the deceased will be able to have these items after they have died. Spirit money (also called Hell Notes) is sometimes burned as an offering to ancestors as well for the afterlife. The living may regard the ancestors as "guardian angels" to them, perhaps in protecting them from serious accidents, or guiding their path in life.
It is in that sense that "ancestor veneration" may convey a more accurate sense of what practitioners, such as the Chinese and other Confucian-influenced societies, see themselves as doing. For example, as "worship" in a Christian context is reserved for the Trinity, a Christian who is unfamiliar with the actual practices and beliefs involved in ancestor-directed rites may mistakenly assume that those who "practice" "ancestor worship" attribute to the ancestors everything that a Christian attributes to the Trinity: creation of the world, omnipotence, a different class of being, etc. This was a possible cause for the initial conflict between the East and Christianity when it was spread to Asia. If one asked a Japanese person if they thought their ancestors were all-powerful or had created the world, the person would probably laugh. In Shinto belief, "Ancestorhood" is a state of being that everyone can attain upon death, so an ancestor is not fundamentally different in the way a deity is.