Do you call your midday meal lunch or dinner?

We all know how confusing the English language is, and coupled with regional variations it is quite surprising that we manage to communicate so effectively.  Or do we?

When my mother-in-law invited me round for dinner I was slightly confused as to whether she meant dinner at lunchtime, or dinner in the evening.  And then there’s the evening meal, which can be tea, supper or dinner!

The ladies who serve meals at lunchtime in schools have always been called ‘dinner ladies’ as opposed to ‘lunch ladies’, however if you took your own to school in a container it was called a ‘lunch box’.

So is it a matter of personal choice? Or is there a right and a wrong?