This is a lens which captures a wider angle of view that normal or, in the case of a zoom, one which offers a 'wideangle' view at its shortest focal length. 28mm equivalent is considered a 'wideangle', while shorter focal lengths are widere still. Most compact digital cameras only zoom out to the equivalent of a 35mm, which doesn't in fact give a particularly 'wide' view. With compact cameras, then, a 'wideangle' lens is a selling point.
Digital SLRs come with kit lenses which offer a minimum focal length of 28mm, so they're all wideangles. You can get super-wideangle lenses which go wider still, though.
This picture was taken with a super-wideangle 14mm equivalent lens, which is about as wide as conventional lenses go without resorting to fisheyes and obvious distortion.
