While grouping pupils may allow teachers to tailor work to ability, staff are determined not to stigmatise young children with a name that is noticeably inferior.
Some have tried asking children to suggest names - but this does not always lead to the tactful, non-hierarchical labels modern teachers favour. One contributor to The TES online staffroom said her charges asked to be divided into gold, silver and bronze.
But some names do give the illusion of equality. Who would guess whether lions were better than tigers? Are buses more able than bicycles?
Sometimes there is a clue in the name. "A school I went to on supply had tigers, tortoises (T for top group), moles (M for middle ability) and leopards and lions (L for lowest ability)," said one teacher.
Another teacher used types of transport - the more wheels they had, the higher the group.
Then there are codes that only teachers can interpret.
One said: "I have found that characters from Winnie the Pooh work really well (and the children have never twigged that Tiggers always has the lively child in, and the Eeyores the grumpy child)." But she warned that the "Pooh Bear" group should be encouraged to use its full name.
While children are happy to be gathered under oblique names that rely on colours or shapes, parents will still always want to know which is the "top" group.
They might also take issue with the school that uses names of vegetables. After all, imagine having to say your child is in the onion set.