[à corde avallée] (Fr.: ‘lowered strings’)
A term sometimes found in lute, guitar and mandore music to designate the alteration in tuning of at least one course of strings from the normal pattern. Such alterations afford players a greater compass of notes, more open strings for resonance and ease of playing. Because of the nature of the tablature notation for these instruments, it is as easy to read and play music in the altered tuning as it is in the normal one.
Apparently, the term appears first in the 16th-century printed sources for four-course guitar (G. Morlaye: Quatriesme Livre … de Guyterne, 1552 [‘corde avallée’], and Le Second Livre, 1553 [‘à corde avallée’]; A. Le Roy: Cinqiesme livre de guiterre, 2/1554, and Second livre de guiterre, 2/1555). Here the term indicates that the fourth (i.e. lowest) course is to be tuned a whole tone lower than usual.
The Spanish term for the normal guitar tuning is ...