I'd avoid the whole phrase, not just the word :-)

OK. That aside, you're right about one thing. The depressions are very rarely central to the stone, perhaps providing a seating area at the side.

The Deerstone is an odd one. There is a confluence of streams at Glendalough and there are around 10 bullaun stones within a very short distance, just as there are now a lot of churches in the same space. This concentration points me towards ritual rather than 'a village quern'.

It's hard to see how a device used for grinding stuff would end up being a device for cursing or curing folks.