SOLUTION: I found the following definition in The Harper Collins Dictionary of Mathematics:
``golden mean, golden section, or extreme and mean ratio, n. the proportion of the division
Question 19413: I found the following definition in The Harper Collins Dictionary of Mathematics:
``golden mean, golden section, or extreme and mean ratio, n. the proportion of the division of a line so that the smaller is to the larger as the larger is to the whole, or of the sides of a rectangle so that the ratio of their difference to the smaller equals that of the smaller to the larger, supposed in classical aesthetic theory to be uniquely pleasing to the eye.''
Those Greek were onto something! Apparently that ``extreme and mean ratio'' is a specific number. In fact it is ________. By the way, don't get put off by the above piece of language which is opaque only because of its brevity. The Harper Dictionary of Mathematics is excellent, despite occasional idiosyncrasies. It's also an inexpensive paperback that I use almost every day, and that I recommend highly as an addition to your library.