This weekend, an important question was raised but not answered by a group of intrepid explorers. Namely: in place names, what does 'Cock' mean? For example - Cockfosters, Cockermouth etc etc.

Is it, simply, chicken? In which case...Cockfosters is somewhere they looked after the chickens?

Or is it, as someone wise suggested, Church? I forget his reasoning but I remember being impressed at the time.

I am not typing 'What does cock mean?' into google at work, as some sort of bad-word alarm will sound and I shall be frogmarched out of the building before I can say 'it's the other kind of cock!'

So. What DOES cock mean?