What does it mean when they say "a DRY martini"?

I love how some people on here have very little idea of what they are talking about yet still give their opinion.

A dry Martini is a way of ordering a Martini with the desired amount of vermouth.

If you ordered a Martini you would probably get it served semi-wet with 1/2oz of dry vermouth
If you order a dry Martini the vermouth is cut in half to about 1/4oz
A very dry Martini just swirls the vermouth round the glass and then dumps it in the sink.
A Martini with no vermouth is a Churchill Martini.

Very little or no vermouth. The name does not really apply to anything other martini's and manhattans.

Less sweet or not sweet.

'Dry' means not sweet. The vermouth is just waved over the glass.