1 : to move (someone or something) back and forth or from side to side [+ obj] ▪ She gently rocked the baby to sleep. ▪ Waves rocked the boat. [no obj] ▪ He rocked back and forth while he stood waiting. ▪ The boat rocked back and forth on the waves. 2 [+ obj] : to cause (something) to shake violently
▪ An earthquake rocked the town. ▪ The building was rocked by an explosion. — sometimes used figuratively ▪ The discovery rocked [=shook] the very foundations of their theory. 3 [+ obj] informal a : to cause (someone or something) to be upset or shocked
▪ The news of the murders rocked the town.
b : to affect or influence (someone or something) very powerfully
▪ Their invention rocked the computer industry.
c : to entertain (someone) in a very powerful and effective way
▪ The band rocked the crowd. ▪ His performance rocked the house. [=the audience loved his performance] ▪ The new video game will rock your world. [=you will really like the new video game] 4 [no obj] informal : to sing, dance to, or play rock music
▪ We were rocking all night long. 5 [no obj] slang : to be very enjoyable, pleasing, or effective
▪ Her new car really rocks. [=her new car is really great]