A triangle circle symbol is known as a Thaumaturgic Triangle. This symbol was a part of the Paranormal Activity movie.
The coven in the film utilized it to call and control a demon at the same time.
This triangle circle symbol, however, depicts the Deathly Hallows in the cinematic adaptation of the fiction book “Harry Potter and the Deathly Hallows.”
Source: https://fbsymbols.net/triangle-circle-symbol/