Transept, croisillon du (transept arm)

A croisillon is one of the arms of the transept.
In plan (Wikipedia) the croisillons are the two parts of the transept north and south of the croisée (crossing).
The picture shows a view on crossing and southern transept arm, taken from the northern transept arm of the Saint-Roch in Passy.
see also transept, bras du (synonym).
For all parts of the transept described above see also all other entries related to transept.

transept - Wikipedia

Saint-Roch - Passy