The term 'ROCK'S PARTNER' can be solved by the crossword solution 'ROLL, ' which is a four-letter word. The term 'ROCK'S PARTNER' is often used to refer to the musical duo of Elvis Presley and Jerry Lee Lewis, who were known for their rock and ROLL music. The term 'ROCK'S PARTNER' is also used to describe the genre of music that was popularized by Elvis Presley and Jerry Lee Lewis, which is commonly referred to as rock and ROLL.