A sonometer is an instrument used to measure sound frequency and waves. Synonyms for sonometer include audiometer, sound level meter, acoustic analyzer, decibel meter, and sound pressure level meter. An audiometer is a device used to measure hearing sensitivity, while a sound level meter measures the intensity of sound in decibels. An acoustic analyzer, also known as a spectrum analyzer, is an instrument used to measure the frequency spectrum and amplitude of sound waves. A decibel meter measures the intensity of sound in a logarithmic scale. Meanwhile, a sound pressure level meter measures the intensity of sound waves as pressure variations in the air. Overall, these synonyms refer to instruments that are used to measure and analyze sound waves.