Special Summons

A special summoning is when you summon a monster, then if you activate effects like Sangan, Monster Reborn, Double Summon or Return From The Different Dimension, you can special summon any monster if you read the text properly.

It doesn't always work however because you can't summon monsters like Silent Magician or Ancient Gear Golem.

A Special Summoning could count as a fusion summoning or a ritual summoning.