A coleopterous insect of the genus Lampyris; esp., the wingless females and larvæ of the two European species (L. noctiluca, and L. splendidula), which emit light from some of the abdominal segments.

the luminous larva or wingless grub-like female of a firefly

A glowworm is a luminous trail of a tiny meteor, occasionally visible in the night sky during a meteor shower.