A turnabout is a word that refers to an act of turning or making a complete U-turn. It usually refers to the act of changing one's decisions completely to the opposite.
In driving maneuvers, the term "turnabout" is used to refer to the need to turn the car around. This can be done by stopping the car, pulls and gets into the other side of the road, turns back, and then move forward to the opposite direction and into the direction it wants to go.
A stock market bubble is a period of growth in stock prices followed by a fall. They often form when traders enter a self-sustaining cycle of growth. They gain momentum as more and more participants enter the market.
