to fall: to drop or go down from a higher place to a lower one, whether by accident, on purpose, or in ruin
At its core this word is simple physical motion: something or someone comes down. Rain beats against a house and it falls; seed drops onto the soil; a person collapses to the ground; a tower topples. The same plain picture stretches in several directions without ever leaving that core.
When a person deliberately goes down to the ground before someone greater, the word describes falling face-down in worship, in pleading, or in fear. The body itself acts out humility and submission. This is by far the most common way the New Testament uses the word, especially in scenes of prayer and worship.
The same downward motion also pictures ruin. A city, a kingdom, or a people that is brought low is said to fall: Babylon is fallen, the walls of Jericho fell, thousands fell dead in the wilderness. And finally the word turns inward, describing a person who once stood firm in faith but comes down from that standing, falling away or coming to nothing. The senses below are all the one act of going down, read in different settings.