There are terms used by Endgame fans and ARG players which although not official, tend to stick and end up being as used as any official one. This page is dedicated to listing them
Name given to Stella Vyctory's rabbit toy that is seen in some photos. When this happens many players immediatly comment using this nickname, almost ignoring everything else.
Olive Fork of TruthEdit
Term mainly used by players of the Sumerian line, it basically represents the lack of any weapon image for a specific bloodline. In the wiki an image of olive forks is used as a filler for lines that don't have a weapon yet revealed.
These are G+ hastags used in the blog by players mainly in the challenges solve page to mark their allegiance.
Seen so far in no specific order are :
Term created by Stella as a joke in Bitter Enemies in the comment section when players wondered in some situations who was controling the camera when there was not supose to be anyone else in the room. The term is now used in videos where this happens and sometimes care is showed for it (Example - if Stella leaves a room and there is still footage, players worry that the Stellacopter got locked in the room)
The XIII or 13th, is a tag players sometimes use. It refers to a fictional group not aligned to any bloodline. It's wrapped in so many misteries that probably even it's "members" don't know them.
After a certain challenge answer was s'more and most non North-American had never heard of it, the term became synonymous with words (mainly solutions) that were too regional for a global audience (for example, regional food, brands , tv shows, etc). Oh , it's a s'more!
Stella joined in the fun by creating a username in youtube called Smores Lover