In my first year of teaching (about 10yrs ago) there was a year4 teacher who had been there so long that she had taught many of the parents.
She called her maths groups; top, middle and bottom. Parents regularly complained and she regularly dismissed their complaints saying that whatever she called them, all children knew 'which' group they were in so she may as well call it as she sees it.
As an NQT I was suitably gobsmacked at this but now I can see that whilst I'd never be so blatant, she was absolutely correct in her reasoning.