Related to magic:
* Incantation: A series of words or phrases used in magic rituals.
* Charm: A magical object or words used for protection or good luck.
* Enchantment: A magical power or effect.
* Hex: A curse or spell intended to cause harm.
Other meanings:
* Period of time: A short period of time, often related to weather. For example, "a spell of hot weather".
* Turn: A period of time spent doing a particular activity, especially in a rotating system. For example, "It's your spell on the watchtower now."
* To name letters: To read aloud the letters in a word, often for someone learning to read.
To give you the best answer, please tell me which meaning of "spell" you are interested in.