I thought as I received notable words from Wordnik's Word of the Day service, I'd post them here. If you like, sign-up for Wordnik's Word of the Day service yourself.
(adj) Shining by night or in the dark; nuctilucid; used especially of certain clouds.
'Noctilucent' is made of the Latin 'nocturnus,' belonging to the night, and 'lucere,' to shine.