Meta terminology
TS
Time Spent
Core Meta engagement metric measuring the aggregate time people spend on a platform. Reported either as a total — "total teen time spent" was set as an overall company goal — or normalized per active user as TS/DAP, which internal decks treat as the standard measure of "engagement."
Sources
Internal documentUnsealed internal messages ("Re: Teens and News Feed Alignment")
Internal documentUnsealed internal messages ("FYI: Teen Growth!!")