The Complete Guide to the ⊐ (Square Original Of) Symbol

The ⊐ (Square Original Of) symbol, sometimes referenced in digital directories as Math Operator 141, is a mathematical character primarily used in set theory and logic to denote that one set is a square superset of another. Found in the Unicode Mathematical Operators block, this symbol resembles a squared-off, blocky version of the standard superset symbol (⊃).

In advanced mathematics, particularly in abstract algebra and domain theory, precision is everything. The ⊐ symbol gives mathematicians a way to distinguish between a standard superset relation and a specialized "square" relation. While the rounded superset symbol implies a general relationship where one set contains another, the square original of symbol often represents stricter ordering, partial orders, or specialized subset relationships depending on the specific mathematical framework.

In the Unicode Standard, the ⊐ symbol is officially named "Square Original Of." It lives at code point U+2290 and belongs to the Mathematical Operators block. This block houses a massive collection of characters designed to make digital math formulas clean, universally readable, and globally standardized.

While you will mostly find ⊐ in academic papers, textbooks, and computer science logic formats, it occasionally escapes into the wild. On social media and messaging apps, users frequently repurpose obscure symbols for text art. Because ⊐ looks like an open box, a sideways cup, or a geometric puzzle piece, it occasionally pops up in creative ASCII art or kaomoji, far removed from its highly technical mathematical origins.

Typing the ⊐ symbol depends on your device and platform. On a Mac, you can use the Unicode Hex Input keyboard and hold Option while typing 2290. On Windows, depending on your setup, you can type 2290 followed by Alt+X in programs like Microsoft Word. For web developers, the HTML entity ⊐ or ⊐ will drop it perfectly into your code. If you are writing a math paper, simply type \sqsupset in LaTeX.

It is easy to confuse ⊐ with its close mathematical relatives. The ⊏ (Square Image Of) symbol acts as its exact opposite, pointing the other way. The standard ⊃ (Superset Of) symbol shares a similar mathematical meaning but features a rounded curve. Finally, the ⊒ (Square Original Of Or Equal To) symbol adds a horizontal line underneath the box, denoting that the sets might also be entirely equal to one another.