moonbow
\MOON-boh\
noun
1. a rainbow caused by the refraction and reflection of light from the moon.
Quotes
A few die-hard photographers have timed their visit to Yosemite Falls so they can catch a glimpse of a rare phenomenon: a rainbow at night, emerging from the mist. It's called a moonbow, and you can only see it a few times a year.
-- Sasha Khokha, "At 150, Yosemite's Roots Go Deep," KQED, June 27, 2014
Origin
Moonbow entered English in the late 1800s and is a blend of moon and rainbow.
Dictionary.com
