Definition from Wiktionary, the free dictionary
See also Appendix:Variations of "x"
Etymology 1 
From French -x.
Pronunciation: usually silent; however, when a distinction is made…
- (Should we delete(+) this sense?) Forms plurals of ‘u’-terminal nouns (and, very rarely, some others) exclusively of French origin.
Derived terms 
Derived terms ending in -eaux
- ^ The Concise Oxford English Dictionary [Eleventh Edition]
Etymology 2 
See also 
- Used to form the regular plural of certain nouns.