Pertaining to the period of time before the catastrophic eruption of Thea, about 1600-1500 BCE, the resultant tsunamis of which are believed to have caused the downfall of the Minoan civilization. This event is thought by many to be the basis of Plato's story of Atlantis. The word literally means "before the flood." From the Latin ante (before) + diluvium (flood).
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.