What is the definition for spelled?

Answer 1

It is the past tense form of the word "spell"

To spell words is an easy task, simply put some letters together.

Writing or naming the letters in general that make up a word.

So saying "Spelt" instead of "Spell" would be talking about how you did it in the past.

Spelt is also the past participle of spell:

She spelt one word wrong and got 9 out of ten right. - past tense

She has spelt all the words wrong. - present perfect - here spelt is the past participle