The term 'beat rhythmically' can be expressed in several ways. The five-letter solution, 'THROB, ' means to beat or PULSATE with a strong, regular rhythm. The seven-letter solution, 'PULSATE, ' means to beat or THROB with a regular rhythm. The four-letter solution, 'DRUM, ' refers to a percussion instrument that is used to create a rhythmic beat. The eight-letter solution, 'PULSATES, ' is the present tense of 'PULSATE, ' meaning to beat or THROB with a regular rhythm.