To plunge headfirst into water. She decided to dive into the pool to cool off.
To descend quickly, often in a controlled manner, such as an aircraft or bird. The plane began to dive rapidly to avoid the storm.
To engage in the sport of diving, which involves jumping into water with acrobatic movements. He loves to dive competitively and has won several medals.
To move quickly or suddenly in a particular direction. He had to dive out of the way to avoid the oncoming car.
To drop sharply in value or amount. The stock prices began to dive after the company's poor earnings report.