Main Entry: knuck·le·ball

Pronunciation: \ˈnə-kəl-ˌbȯl\

Function: noun

Date: 1910

: a slow baseball pitch that moves erratically and unpredictably and that is thrown with little spin by gripping the ball with the knuckles or the tips of the fingers pressed against the top

— knuck·le·ball·er \-ˌbȯ-lər\ noun