The purpose of this word, or any word, is to enable the golfer to get lost in what he is doing at that moment. The end result is complete concentration on the process of hitting the ball. Another strategy is to develop rituals. Consistently use the same ritual. It can be touching your right sock with your left hand before you get into your stance.
Rituals help to blank the mind and place focus on the ball.
If All Else Fails If developing a solid mental approach does not appear to help, maybe the problem isn't mental. A golf professional can help to identify problems with mechanics or physical conditioning. Whatever your need, stay calm. This is a game. Remember, you play golf because you enjoy it.