The triangle symbol (△) is used in math to reference a triangle in a diagram.
KRATOS TRIANGLE RING – Felicity Anne Design
△ - WHITE UP-POINTING TRIANGLE (U+25B3)
Mastering CSS Triangle: How to Create All Kinds of Triangles - Blogs
Free Vectors Simple symbol triangle mark (△ black)
What is the three triangle symbol? - Quora
Triangle
Entropy, Free Full-Text
△ - Wiktionary, the free dictionary
Triangle
The meaning of Metal Gear Solid Triangle explained : r