A sticky material produced from the stump and roots of pine trees. In baseball it is widely used on the handle of bats to provide extra grip and prevents slippage.
While it's perfectly legal to use pine tar on bat handles (up to
18 inches from the end of the bat), it is illegal for pitchers to
use the substance on the ball to improve grip and increase spin on
Over the years there have been several instances of pitchers ejected from games for using pine tar. Typically the pitcher spreads some on their glove so they are able to apply to the pitching hand whenever required.