What's the difference between orthography and spelling?

The terms "spelling" and "orthography" seem to be largely synonymous. What is the difference really? Is it that "orthography" is a more formal or technical term and hence more well-defined? Or is it just a fancy word to make me sound smarter when saying the same thing? (-:

I agree, they sound similar and synonymous, but they have a definite difference.

Like Lefteris Gkinis said, orthography comes from the Greek and means "Correct way of writing".

It includes also punctuation and spelling. So, rather than a mere activity, it's the part of the Grammar that studies, and is related to, the correct way of writing, whether it is about single words, punctuation, etc.

The spelling, like the NOAD says, is "the process or activity of writing or naming the letters of a word." So it's something more specific, since it's only related to how the single words are "made".

In order to answer your question, we have to first investigate the exact meaning of orthography. Orthography is the standardized procedure of a writing system, which includes punctuation, capitalization, word breaks, emphasis, etc. This means that spelling is only a part of orthography(spelling is part of a writing system), but orthography includes a lot more than just spelling. That is where the difference between orthography and spelling lies.