蓝烟火光；孟加拉烟火；信号烟火（等于Bengal fire）

[ noun ]
a steady bright blue light; formerly used as a signal but now a firework
<noun.communication>

Bengal \Ben*gal"\, prop. n.
1. A province in India, giving its name to various stuffs,
animals, etc.

2. A thin stuff, made of silk and hair, originally brought
from Bengal.

3. Striped gingham, originally brought from Bengal; Bengal
stripes.

{Bengal light}, a firework containing niter, sulphur, and
antimony, and producing a sustained and vivid colored
light, used in making signals and in pyrotechnics; --
called also {blue light}.

{Bengal stripes}, a kind of cotton cloth woven with colored
stripes. See {Bengal}, 3.

{Bengal tiger}. (Zo["o]l.). See {Tiger}.