《荀子·大略》
弯腰后头与腰相平叫做拜，头比腰低叫做稽首，头着地叫做稽颡。
平衡曰拜，下衡曰稽首，至地曰稽颡。
Bending over to make one's head level with one's waist is called a 'bai,' lowering one's head lower than one's waist is called a 'jishou,' and touching one's head to the ground is called a 'jisan.'