It was the official Blizzard name for the difficulties (10-man and 25-man) at the start.
Few players used it (that I know of) - but to claim that the official name was never used is as many of your other statements plain wrong.
Just look at https://www.wowhead.com/the-obsidian-sanctum#comments from 2008:
And also from Blizzard: http://eu.battle.net/wow/en/game/patch-notes/3-1-0First boss: Assign 4 (or 10 on heroic) people, including tank and healers to go through the portal every time, and kill the add that spawns in there. The rest stays on the boss, that's pretty much it.
This raid is extremely easy on heroic mode (25 man).
After doing the instance on normal (10 man) this is a joke with killing the dragons, if the groups half organized I recommend attempting to leave one dragon up for the extra loot. A complete write up on the instance in the 10 man.
Eye of Eternity
Malygos will now properly delay before breathing after a Vortex on Heroic difficulty.
The key to that instance was: https://www.wowhead.com/quest=13375/...-focusing-iris