white night

This is not an oxymoron either… they exist. St Peter’sburg in Russia is famous for it’s summer white nights. It is so close to the artci circle that summer nights are never dark.

Also there is a term used in banking for an investor who rescues a company from bankruptcy or hostile takeover called a WHITE KNIGHT… also not an oxymoron, but a historical reference to the heroic knight of legend (as opposed to the evil black knight).