Concise Bible Dictionary:
An act of respect between man and man, very common in the East, as Abraham bowed down himself before the people of the land when he bought a burying place for his dead (Gen. 23:7, 12). Also an act of reverence to God (Psa. 95:6); but strictly forbidden to be done before an idol or image (Ex. 20:5); and treated as an act of worship.