Jim, when you think of a wing, you usually think of a rectangle shape where the span is greater than the chord. In most cases this is true. the ratio is the difference between the span and the chord. A low aspect ratio wing will still have a longer span that the chord but the differece is not as great To be honest I could not tell you where the cut off point where the high aspect ratio ends and the low aspect ratio starts.

in street talk a high aspect ratio wing, sometimes only referred to as a high aspect wing is one that is relatively long span with a short chord. You might call it long and slender.
A low aspect wing is shorter in span with a wider chord. You might call it a stubby wing
The there are extremes where you would say a very high or very low aspect ratio.
A very high aspect would be likw a sailplane.
A very low aspect wing would be one that for instance the chord was as great or greater than span!
Without pictures it is a little hard to understand so I am providing a link that explains in more technical detail.
http://en.wikipedia.org/wiki/Aspect_ratio_(wing) This link will provide some pictures that will help you to understand.

In the first picture below the red plane is a high aspect wing compared to the other plane. In the second picture below shows what would be a very low aspect ratio wing.
I hope this helps some, LT