Special Summon Monster
Special Summon Monster is any monster that has a a rule or condition prevents it from being Normal Summoned and Normal Set. It often has a Summoning Condition that restricts how the monster must be Special Summoned. Therefore, most of those monsters considered Nomi monsters or Special Summon-only monsters.
Alternately, a Normal Summon Monster is a monster without these restrictions, and can be Summoned and Set Normally.
