The sample rate is the number of samples played in each second. Sample rates are measured in "Hertz" (abbreviated "Hz"), which means "per second," or in "kilohertz" (abbreviated "kHz"), which means "per second, times one thousand." The sample rate used on audio CDs can be written as 44 100 Hz, or 44.1 kHz, which both have the same meaning. Common sample rates are 44.1 kHz, 48 kHz, and 96 kHz. Other possible sample rates include 22 kHz, 88.2 kHz, and 192 kHz.