What is the meaning of sacrifice in the perpetual calendar? thank you

Sacrifice refers to a series of symbolic acts or ceremonies to worship gods and ancestors according to the requirements of religion or social customs. According to the religious and folk interpretation of Ci Hai, sacrifice: refers to offering sacrifices to gods, ancestors or mourning the dead with ceremonies. Such as offering sacrifices to heaven, ancestors and public sacrifices; Sacrifice: refers to offering sacrifices to gods and ancestors.