Quenya 

ceuran-

new moon

ceuran- ("k") noun "new moon" (compare Rána "moon"). The word is cited with a final hyphen, as if some final element is missing, but Rána could very well be reduced to -ran at the end of a compound. (VT48:7)

Sindarin 

cýron

new moon

cýron (i gýron), pl. cýroen (i chýroen). Archaic *cýraun, spelt cýrawn in the source (VT48:7).