A Ritual Summon is a Special Summon that is conducted through the effect of a Ritual Spell Card. These Summons usually require Tributes greater than or equal to the Level of the monster being Summoned, from either your side of the field or your hand, however, some cards such as End of the World require them to have the exact level requirement.
A Monster that was properly Ritual Summoned can be Special Summoned from the Graveyard unless otherwise dictated on a card's text.
Types of Monster Cards
Types of Spell Cards
Types of Trap Cards
ATK • DEF • Level • Attribute • Type
Playing Field Zones
Types of Summon
Types of Monster Effects
Types of Effect Monsters
Types of Spell Speed
Aqua • Beast • Beast-Warrior • Dinosaur