I assume the words classic and classical have a basis in the word class — which is to say, of a category. Why do we use those words to mean old or historically important?
Here's a shot at it, not sure if this is accurate but is logical.
Two definitions of the word can combine to form this meaning of Historic.
The first is
of the first or highest quality, class, or rank
The second is
serving as a standard, model, or guide.
I would say, the classic model is also the highest quality model. You can't know the classic model unless it is in the past. Thus, the usage of the word describes something of high quality, in the past.
A classic model for economic growth would be one that is proven to work because of its high quality, It is possible that the fact that it has taken place in the past serves its base for being an historical word.
These and other definitions of classic: dictionary.reference.com/browse/classic?s=t
Historically important usually has some values to the place or item in place. Values as in something to do with its history and it being old.
Definition of classical
- relating to ancient Greek or Latin literature, art, or culture:
Definition of classic
- judged over a period of time to be of the highest quality and outstanding of its kind: a classic novel a classic car
- work of art of recognized and established value: his books have become classics - garment of a simple, elegant, and long-lasting style. - thing which is memorable and a very good example of its kind: he’s hoping that tomorrow’s game will be a classic.
http://oxforddictionaries.com/definition/english/classical http://oxforddictionaries.com/definition/english/classic http://www.merriam-webster.com/dictionary/classic http://www.merriam-webster.com/dictionary/classical