The Mathematical Symbol "Square Cap (⊓)"

The "Square Cap" Symbol (⊓)

The ⊓ symbol, also known as "Square Cap," is a mathematical representation used in various contexts. It can be visualized as two overlapping squares. In set theory, especially, it's used as an intersection operation for certain kinds of sets.

Understanding the Symbol

The ⊓ is reminiscent of the intersection symbol in set theory, but it's squared. It represents the intersection of two sets, similar to how the regular cap (⋂) does, but it can be used in specific contexts or with certain types of sets.


This symbol is mainly used in set theory and Boolean algebra. In set theory, it denotes the intersection of two sets, meaning it represents all the elements that are common to both sets.

For instance, when representing the intersection of two sets A and B, one might use this symbol as in \( A \sqcap B \).


Consider two sets:

A = {1, 2, 3, 4}

B = {3, 4, 5, 6}

The intersection of sets A and B would be:

A ⊓ B = {3, 4}

Typing ⊓

In web-based platforms or digital documents that support HTML entities, inputting the ⊓ entity will render the "Square Cap" symbol. The exact appearance might differ based on the selected font and platform. In other environments, a specific keyboard shortcut or code might be needed.

Related Symbols

There are various related symbols in set theory, such as:

  • ∩ (Intersection)
  • ∪ (Union)
  • ⊔ (Square Union)


The ⊓ symbol plays a vital role in mathematical contexts, particularly when discussing the intersection of sets or in Boolean algebra. It offers a square-shaped alternative to the traditional cap symbol used for intersections.

Mathematical symbol 'Square Cap'

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Codes for the ⊓ Symbol

The Symbol
Alt CodeAlt 8851
HTML Code⊓
HTML Entity⊓
CSS Code\2293
Hex Code⊓

How To Insert the ⊓ Symbol

(Method 1) Copy and paste the symbol.

The easiest way to get the ⊓ symbol is to copy and paste it into your document.

Bear in mind that this is a UTF-8 encoded character. It must be encoded as UTF-8 at all stages (copying, replacing, editing, pasting), otherwise it will render as random characters or the dreaded �.

(Method 2) Use the "Alt Code."

If you have a keyboard with a numeric pad, you can use this method. Simply hold down the Alt key and type 8851. When you lift the Alt key, the symbol appears. ("Num Lock" must be on.)

(Method 3) Use the HTML Decimal Code (for webpages).

HTML TextOutput
<b>My symbol: &#8851;</b>My symbol: ⊓

(Method 4) Use the HTML Entity Code (for webpages).

HTML TextOutput
<b>My symbol: &sqcap;</b>My symbol: ⊓

(Method 5) Use the CSS Code (for webpages).

CSS and HTML TextOutput
span:after {
content: "\2293";}
<span>My symbol:</span>
My symbol: ⊓

(Method 6) Use the HTML Hex Code (for webpages and HTML canvas).

HTML TextOutput
<b>My symbol: &#x2293;</b>My symbol: ⊓
On the assumption that you already have your canvas and the context set up, use the Hex code in the format 0x2293 to place the ⊓ symbol on your canvas. For example:
JavaScript Text
const x = "0x"+"E9"
ctx.fillText(String.fromCodePoint(x), 5, 5);

(Method 7) Use the Unicode (for various, e.g. Microsoft Office, JavaScript, Perl).

The Unicode for ⊓ is U+2293. The important part is the hexadecimal number after the U+, which is used in various formats. For example, in Microsoft Office applications (e.g. Word, PowerPoint), do the following:
[Hold down Alt]
[Press x]

(The 2293 turns into ⊓. Note that you can omit any leading zeros.)
In JavaScript, the syntax is \uXXXX. So, our example would be \u2293. (Note that the format is 4 hexadecimal characters.)
JavaScript TextOutput
let str = "\u2293"
document.write("My symbol: " + str)
My symbol: ⊓