Woods are used to hit long shots. If a golf hole is 450 yards from tee to green, most golfers use a wood to hit off the tee. A wood is a hollow-bodied large headed golf club. Use your woods when you are 175 yards or more away from the green.
The DRIVER has the lowest loft of any golf club. Loft is the angle of the club face that controls trajectory and affects distance. A driver has a loft between 7 and 12 degrees. Experienced golfers have traditionally favored lower lofted drivers (less than 10 degrees of loft), which require much more skill to hit than higher lofted drivers.
3 and 5 WOODS come after the driver. A 3 wood has a loft between 15 and 18 degrees, and a 5 wood has a loft between 20 and 22 degrees. The higher the golf club number, the higher the loft. In addition, the higher the golf club number, the shorter the club. A 3 wood is generally 1/2 shorter than a Driver and so on with each successive club. There are 7 and 9 WOODS, and they provide more forgiveness if you also want distance in your shots.
The 3 wood and 5 woods are commonly referred to as FAIRWAY WOODS, because they are most often used during the second shot of play, when you are supposed to be in the fairway of the golf. All higher lofted woods, such as 7-9-11, are commonly referred to as UTILITY WOODS.
IRONS are generally used when you are less than 200 yards away from the green. The closer you are to the green, the higher the iron you will use. A standard set of irons consists of 3, 4, 5, 6, 7, 8, 9 IRONS and the PITCHING WEDGE. The 3 and 4 irons are harder to hit than the higher number irons. Many golfers, especially ladies, seniors and higher handicap golfers are changing to a modified standard golf set that replaces the 3 and 4 irons with higher lofted woods like the 7 and 9 woods. Higher lofted woods, like the 7 and 9 woods are easier to hit than a 3 or 4 iron and result in comparable distances.
WEDGES are really just specialty irons. The first wedge is the Pitching Wedge (PW), which is usually about 48 degrees in loft. Wedges generally increase in 4 degree loft amounts, commonly coming in 48, 52, 56, 60 degree lofts.
Wedges are extremely useful to your game and most golfers have a few of them. Wedges are generally designed as "blade clubs" because you are close enough to the green that the game improvement design elements (discussed below) are less important. The need for increased shot control and shot shaping, which blade design encourages, becomes the more important technology for a good wedge design.
A PUTTER is a golf club with a special purpose: getting the ball into the hole when you are on the green. After you have slammed your drive, hit the ball deep to the left in the rough, and then wedged out onto the green, it is time to putt. The putter is used on the green and there are many style of putters: short, belly, long, bent, center-hosel, heel-toe, and mallet. There are other ones, but these are the most common.