NotRightTriangleBar 
NotRightTriangleBar[x,y,…]
displays as .
Details

- NotRightTriangleBar[x,y,…] has no built-in meaning.
is by default interpreted as NotRightTriangleBar[x,y].
can be entered as \[NotRightTriangleBar].
Examples
Basic Examples (1)
Wolfram Research (1996), NotRightTriangleBar, Wolfram Language function, https://reference.wolfram.com/language/ref/NotRightTriangleBar.html.
Text
Wolfram Research (1996), NotRightTriangleBar, Wolfram Language function, https://reference.wolfram.com/language/ref/NotRightTriangleBar.html.
CMS
Wolfram Language. 1996. "NotRightTriangleBar." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/NotRightTriangleBar.html.
APA
Wolfram Language. (1996). NotRightTriangleBar. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/NotRightTriangleBar.html