what's in a name?

well, in potterverse, rather a lot i think!

my dad and step mum were over yesterday. grandad got into a very involved conversation with ds(4) about the colours and decoration on a shield he was making out of cardboard. grandad warned him to put the band across it the correct way so as not to have a something 'sinistra'.

so is the astronomy professor a snitch of some sort? they (is it a she?) are only mentioned in passing from time to time, but the astronomy tower is quite significant....