Epic Spell: Spells that are different from common spells. Epic spells are usually custom-made. Epic spells do not take up normal spell slots, but instead are gained and used under a completely separate progression.
Epic Spell Slots: A character must have an available epic spell slot to prepare or cast an epic spell, just as he or she needs a normal spell slot for a nonepic spell. A character doesn't gain epic spell slots by virtue of his or her level and class, however. A character gets one epic spell slot for every 10 ranks he or she has in the relevant Knowledge skill.
Factor: When creating an epic spell, a character can modify the basic use of a seed. Each modification is called a factor, and most factors increase the difficulty of casting the spell.
Mitigating Factor: The opposite of a normal factor, a mitigating factor modifies the spell but makes it easier to cast.
Seed: Every custom epic spell created by spellcasters begins with a base effect called a seed. Seeds are the fundamental building blocks of epic spells.
Spellcraft DC: For epic spells, the Spellcraft DC is a measure of how difficult the spell is for a spellcaster to cast. It also measures how powerful an epic spell is.