Plato's beard

Plato's Beard is a phrase that is used to describe something that is very ancient or old-fashioned. It comes from a story about the famous Greek philosopher, Plato. According to the story, a student of Plato's once asked him what his beard was like. Plato replied that his beard was so long, it reached all the way to heaven! Because Plato lived thousands of years ago, his old-fashioned ideas, thoughts and theories have been around for a long time - just like his beard! So, when we talk about something being 'Plato's Beard', we mean it is very old-fashioned.