Dry MartiniFor the first time Dry Martini was mentioned in American literature in 1903. In the 1920-s both dry and sweet varieties of Martini were getting extremely popular in the US.
What makes it 'dry' is the reduced amount of the vermouth. Of course, the proportion can be quite personal to every drinker - some like it 'dry', some like it 'wet'. You can make variations that affect the name of the drink: a classic Martini would have some gin to it and quite a splash of dry vermouth. A Dry Martini is going to have lots of gin and just a subtle additoin of dry vermouth whilst a Very Dry Martini (that is usually a popular wish to be heard at the bars) is going to be pretty much only gin. Some assert there's a so-called Dirty Martini which implies that you add some olive juice to the cocktail and definitely put an olive on the bottom of the glass.
Naturally, you won't know which variant you like most until you've tried them all. So you might as well start doing so now.