A foundation stop at 5-1/3' pitch in the manuals, or 10-2/3' in the pedal. It is made in a variety of forms, including wood, metal, open, stopped, or half-stopped. The Gros Nasard of the French classical organ was, like all mutations of that time and place, of wide scale.
Examples:
The names Quint and Quinte are extremely common. Osiris contains about two dozen examples of Gross[e] Quint[e] at 10-2/3' pitch (all in pedal divisions), and about two dozen at 5-1/3'. No examples of Double Twelfth (mentioned only by Hopkins & Rimbault) or Sub Tierce are known. Contributions welcome.
Fifth 5-1/3', Choir-Swell; Convention Hall, Atlantic City, New Jersey, USA; Midmer-Losh. (This is the only known example of the name Fifth, used by itself.)
Grossnasat 10-2/3', Pedal; Sejong Cultural Center, Seoul, Korea; Schuke 1978.
Grossnasat 5-1/3', Hauptwerk; Opera House, Sydney, Australia; Sharp 1979.
Grossnassat 10-2/3', Pedal; Cathedral, Merseburg, Germany; Ladegast 1853.
Gros Nasard 10-2/3', Pedale; First Baptist Church, Winston-Salem, North Carolina, USA; Moller 1969.
Gros Nasard 8' [sic], Pedale; St. Denis, Paris, France; Cavaille-Coll 1841. (The pedal compass was FF-F0, so the pitches of the unison and octave sounding stops were given as multiples of 3, and this Gros Nasard at 8' was really a fifth-sounding stop.)
Gros Nasard 5-1/3', Grand Orgue; Notre Dame des Victoires, St. Raphael, Provence, France; Cabourdin 1987.
Megalopente 10-2/3', Pedal; Coliseum, Boston, Massachusetts, USA; Wilcox & Co.