Oftentimes when describing flying organisms and vehicles, their wings are said to have a "high aspect ratio" or a "low aspect ratio". Sometimes the papers (that I read) gave the numbers, but more often, they would just leave the explanation at that.

So I was wondering, in general, what is the minimum ratio that would make it a "high AR" and what is the minimum ratio that would make it a "low AR"? Is there a threshold to be met, or is this analysis of AR rather relative and or subjective?