noun /ˈspelɪŋ/
a) The act, practice, ability, or subject of forming words with letters, or of reading the letters of words; orthography.
For the practical use of spelling comes in writing.
b) The manner of spelling of words; correct spelling.
Spelling was invented by man and, like other human inventions, is capable of development and improvement by man in the direction of simplicity, economy, and efficiency.
Wikipedia foundation.