Stephen Fry and Rob Brydon in “Unfinished Business”

Stephen Fry

There is this strange thing called libration, which is like vibration but beginning with an L. It was a thing that was noted by quite a few of the early astronomers...

Rob Brydon

Can I say, sorry Stephen, but that's not an acceptable way of defining a word: Libration. It's like vibration, but beginning with an L.