Simul-Cast

From the Rulebook Glossary:
This refers to the ability of some magic to be cast more than once at the same time. Simul-cast enchantments cannot be worn with more than one layer of other simul-cast enchantments, even with the Stack magic or similar class abilities. When simul-casting magic you must repeat the incantation once for every layer of the enchantment to be cast or magical ball to be charged. You may not add more layers to simul-cast magic after the initial casting.

See Also: Simul-cast.