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|