Light; a lamp or source of illumination. Often used in a slightly literary or old-fashioned sense.
暗い部屋に一つだけ灯がともっていた。
Only one lamp was lit in the dark room.
古い町並みには暖かい灯が似合う。
Warm lights suit the old townscape.
祭りの夜、行灯に灯を入れて街を飾った。
On the festival night, they lit lanterns to decorate the town.