For the most part, the number "represents" the loft of a club. The lower the number, the lower the loft and the longer the club. The lower loft and longer club will result in greater distance with a loss of accuracy. This also equates to lower numbered clubs being more difficult to hit (if all the golf club jargon is confusing to you you can check an extensive collection of definitions HERE.)
A "set" of golf clubs is restricted
to no more than 14 clubs. What constitutes this "set" depends on your preferences. In general, a "set" will include
the following clubs:
This is not to say you have to carry all of these clubs. For example, a beginner may carry a Driver (1 wood) or 3 wood, a 3, 5, 7, and 9 iron, as well as a putter. Some manufacturers let you configure a set to your needs, so you don't need to but what you don't want. Pinemeadow Golf is a good example for such a flexible company.
A good basic descriptions of the clubs is provided by Pinemeadow Golf.
Lie is the angle that the hosel of the iron makes with the rest of the iron head (an introductory article on golf club heads can be found HERE). Generally, each iron has a hosel - this is the part of the iron that connects with the shaft - that projects out from the clubhead at standard lie. By adjusting the hosel the lie of the club or the angle that the hosel forms with the rest of the iron head can be altered to better fit a player's physical characteristics.
The most important part of the golf club is by far the shaft (an introductory article on the components of a golf club can be found HERE). And one of the most important aspects of the shaft is the shaft flex. Flex refers to the stiffness of the shaft. If you are in a golf shop and look at various golf shafts and waggle various golf clubs you will see that some shafts are stiffer than others. The stronger a player is, the stiffer the shaft that he or she wants.
The stronger a shaft the less flexible it is. When a player swings a club the clubhead acts as a weight at the end of the club and causes the shaft to bend. On the downswing the player causes the shaft to bend as he or she throws the clubhead at the ball. If a shaft is too flexible and is bending too much then it becomes impossible for the player to control where the ball is going to go. The bend in the shaft is where much of the power is generated in the shot. If the shaft doesn't flex enough then the shot loses power and accuracy is affected. So you want to pick a shaft that gives you the right amount of flex. You should also keep in mind that every manufacturer has different grades or quailities of shafts, and you should look out that you don't get the rejects which are sold by some cheap companies.
In general the stiffer the flex of a shaft the more accurate the shot, but the less far it goes. Use the chart below to help you pick the right shaft flex for your game (again these are only suggestions and LearnAboutGolf.com is not responsible if they don't work for you, and in case this sounds too confusing please visit the free 'club fitting wizard' at Pinemeadow Golf).