Sindarin 

noun. bow, bow; [N.] arch, crescent; [G.] waxing or waning moon

Sindarin [PE17/122; S/209; SA/cú] Group: Eldamo. Published by

bow

(i gû, o chû) (arch, crescent), pl. cui (i chui)

eilian

rainbow

(pl. eiliain). Archaic elianw (so the coll. pl. may be eilianwath).

peng

bow

(i beng, o pheng), pl. ping (i phing)