Reentrant tuning

On a stringed instrument, a break in an otherwise ascending (or descending) order of string pitches is known as a re-entry. A re-entrant tuning, therefore, is a tuning which does not order all the strings (or more properly the courses) from the lowest pitch to the highest pitch (or vice versa).

Most common re-entrant tunings have only one re-entry. In the case of the ukulele, for example, the re-entry is between the third and fourth strings, while in the case of the Venezuelan cuatro it is between the first and second strings.