So .... it's Wednesday, and looks like I'm the only person on the planet who can't get 52d: Muse in class on heavenly body. I'm sure it's going to blindingly obvious, but can someone oblige please!
It's better/more helpful/more polite if you give the numbers of letters in the answer and details of what you have.
I think this was Clio - one of the Muses in greek mythology. 'Cl' is class and 'io' is a planet/constellation/something similar,.