X nomenclature (from the IAU and from unofficial sources)

Italics indicate farside features.

X (Lunar X) (well known clair-obscur phenomenon)
-Caes- X crater (Mercator A, which has an X-shaped system of dark radial bands on its inner slopes)
-Riccioli- Xenophanes
-Van Langren- Xenophanis (IAU: Strabo)
Xenophon