What is a 18-55mm lens digital camera? What do the numbers mean?

Thank you.

18-55mm is the actual focal lengths of a zoom lens. However, when used on a digital camera, there has to be a 35mm equivalent conversion factor that you'll need to find out from the manufacturer. For example, the latest Nikon D80 has 1.5x conversion factor and Canon XTi has 1.6x. That means, when you use the same the lens on Nikon, you get 1.5x(18-55)=27-82.5mm equivalent to a 35mm film camera; while on Canon, you get 1.6x(18-55)=28-88mm equivalent (of course you can't use the same lens on both Nikon and Canon because the mount is different).

One step further, the smaller the focal length, the wider view you'll get in the picture. Therefore people usually refer to the lower number as "wide angle", and the higher number as "telezoom". Now in the above Nikon and Canon cases, this is a decent lens for wide angle (however, to completely rate the lens, you'll have to find additional specs such as the aperture or f-number), but the telezoom will not be very impressive and people frequently pair it up with a telezoom lens, say 55-200mm.

this is a shot in the dark here, but i think it refers to the lens sizes on the ends of the lens, if that makes sense. as in before the reciever, the window is 18mm, and to the outside world the lense is 55mm

The 18-55mm lens refers to the focal length of the lens. In this case this is variable focal length lens or what many refer to as a zoom lens. To give you a frame of reference, the standard lens on a 35mm SLR camera is usually a 50mm lens.

An 18-55mm lens would be a reasonable wprking lens for casual use - indoor and outdoor shots of family, and other stuff.

SLR cameras - both film and digital - have the ability to change lenses. There is a wide variety of lenses available for SLR cameras. Many photographers like to have a selection of lenses from about 35mm to about 400mm. Lens larger than 400mm start to get more expensive and not everyone can afford them.

and here are some links that help explain all about focal length...

that means the lens is 18-55mm away from the film(in this case the digital sensors) I don't know how much optical zoom that is to compare to other dig cameras, maybe 3x