spelling (Noun) — Forming words with letters according to the principles underlying accepted usage.
spelling (Verb) — Specify or name the letters that comprise the conventionally accepted form of (a word or part of a word). ex. "He spelled the word wrong in this letter"
spelling (Verb) — Orally recite the letters of or give the spelling of. ex. "How do you spell this word?" ex. "We had to spell out our names for the police officer"
spelling (Verb) — Indicate or signify. ex. "I'm afraid this spells trouble!"
spelling (Verb) — Relieve (someone) from work by taking a turn. ex. "She spelled her husband at the wheel"
spelling (Verb) — Place under a spell.
spelling (Verb) — Take turns working. ex. "the workers spell every four hours"