The definition of a shit that is so large in mass that it rises over the water in the toilet bowl. To do so one must shit so that there is a solid base under the water level.

The moment after you ejaculate where you can’t physically go any longer. No matter how hard you try you can’t get past that point, hence “The Event Horizon.”

The darkened area of skin which surrounds the asshole.

The exact moment in time between when a person realizes that they are going to have diarrhea and that it is inevitable.

In physics, the event horizon is the "point of no return" in which an object is caught in the gravitational pull of a black hole.

The original definition is:
"The gravitational sphere of a black hole within which even light cannot escape"
-Wikipedia

However, recently, a new definition has risen meaning something completely different:
The Event Horizion is the point at which a person is too drunk or stoned to be able to function properly, yet alone remember anything the next day.

The thing that comes out of the stargate wen it its diales makes a woosh kind of sound.

the area on the side of a girl's face where her make-up partially blends with her actual skin, though still in a very noticeable way.