The cent is a logarithmic unit of interval measurement equal to 1/1200 of an octave, which is equivalent to one hundredth of a semitone in the case of twelve-tone equal temperament. Cents are used to compare comparable intervals in different tuning systems.
The ability of humans to distinguish very small differences in pitch depends on a number of factors, including the frequency, amplitude and timbre of the sounds as well as the individual's hearing ability. A one cent difference in pitch is far too small for humans to recognize, but some researchers state that in ideal circumstances many young adults can recognize a difference of about five or six cents.