A transverse rib (french: arc doubleau) is the term in

architecture Architecture is the art and technique of designing and building, as distinguished from the skills associated with construction. It is both the process and the product of sketching, conceiving, planning, designing, and constructing building ...

given to the rib of a

rib vault A rib vault or ribbed vault is an architectural feature for covering a wide space, such as a church nave, composed of a framework of crossed or diagonal arched ribs. Variations were used in Roman architecture, Byzantine architecture, Islamic ...

which is carried across the

nave The nave () is the central part of a church, stretching from the (normally western) main entrance or rear wall, to the transepts, or in a church without transepts, to the chancel. When a church contains side aisles, as in a basilica-type ...

, dividing the same into

bays A bay is a recessed, coastal body of water that directly connects to a larger main body of water, such as an ocean, a lake, or another bay. A large bay is usually called a gulf, sea, sound, or bight. A cove is a small, circular bay with a narr ...

. Although as a rule it was sunk in the

barrel vault A barrel vault, also known as a tunnel vault, wagon vault or wagonhead vault, is an architectural element formed by the extrusion of a single curve (or pair of curves, in the case of a pointed barrel vault) along a given distance. The curves are ...

of the ''

thermae In ancient Rome, (from Greek , "hot") and (from Greek ) were facilities for bathing. usually refers to the large Roman Empire, imperial public bath, bath complexes, while were smaller-scale facilities, public or private, that existed i ...

'', it is found occasionally below it, as in the piscina at

Baiae Baiae ( it, Baia; nap, Baia) was an ancient Roman town situated on the northwest shore of the Gulf of Naples and now in the ''comune'' of Bacoli. It was a fashionable resort for centuries in antiquity, particularly towards the end of the Roman ...

and the so-called

Baths of Diana Diana's Baths is a series of small waterfalls located in the southeastern corner of the town of Bartlett, New Hampshire, near the village of North Conway, New Hampshire, North Conway in the White Mountains (New Hampshire), White Mountains of New ...

(

Nymphaeum A ''nymphaeum'' or ''nymphaion'' ( grc, νυμφαῖον), in ancient Greece and Rome, was a monument consecrated to the nymphs, especially those of springs. These monuments were originally natural grottoes, which tradition assigned as habit ...

) at

Nîmes Nîmes ( , ; oc, Nimes ; Latin: ''Nemausus'') is the prefecture of the Gard department in the Occitanie region of Southern France. Located between the Mediterranean Sea and Cévennes, the commune of Nîmes has an estimated population of 148,5 ...

. In the Romanesque and

Gothic Gothic or Gothics may refer to: People and languages *Goths or Gothic people, the ethnonym of a group of East Germanic tribes **Gothic language, an extinct East Germanic language spoken by the Goths **Crimean Gothic, the Gothic language spoken b ...

styles it becomes the principal feature of the vault, so much so that ScottRobert A. Scott, ''The Gothic Enterprise: A Guide to Understanding the Medieval Cathedral'' University of California Press (2003) termed it the "master rib".

References

* Arches and vaults Church architecture {{Church-architecture-stub