The Mathematical Symbol "Square Original Of (⊐)"

The "Square Original Of" (⊐)

The ⊐ symbol, commonly known as "Square Original Of", is a mathematical notation with usage that parallels the "Square Image Of" symbol. While not as commonly utilized in many texts as other set relations, it has specific roles in particular mathematical contexts.

Understanding the Symbol

The ⊐ symbol is often used to represent the idea that one set, say A, is an original set from which another set, B, derives its elements under a specific function or relation. This symbol conveys the notion of one set being the origin for another in a particular context.


The exact usage of ⊐ can be niche and might be context-dependent. Its primary function is to clarify relationships between sets in mathematical situations where standard subset notations might be insufficient or might lead to ambiguity.


Consider a function \( f: A \to B \). Using the ⊐ notation, we might express:

\( A ⊐ B \) under \( f \)

This notation indicates that set A is an original set from which set B derives its elements under the function \( f \).

Typing ⊐

In digital documents or on the web, using the ⊐ entity will render the "Square Original Of" symbol. When working with certain mathematical software or notation systems, different methods might be required to display or input this symbol.

Related Symbols

Other symbols that might be considered related include ⊐ (Square Superset Of) and ⊒ (Square Superset of or Equal To). Each symbol provides specific nuances about the relationships between sets.


The use of the ⊐ symbol, like many mathematical notations, arises from the need for precision in describing certain mathematical relationships. Understanding its proper context and usage can aid in more accurate and clear mathematical communication.

Mathematical symbol 'Square Original Of'

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Codes for the ⊐ Symbol

The Symbol
Alt CodeAlt 8848
HTML Code⊐
HTML Entity⊐
CSS Code\2290
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 8848. 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: &#8848;</b>My symbol: ⊐

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

HTML TextOutput
<b>My symbol: &sqsup;</b>My symbol: ⊐

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

CSS and HTML TextOutput
span:after {
content: "\2290";}
<span>My symbol:</span>
My symbol: ⊐

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

HTML TextOutput
<b>My symbol: &#x2290;</b>My symbol: ⊐
On the assumption that you already have your canvas and the context set up, use the Hex code in the format 0x2290 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+2290. 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 2290 turns into ⊐. Note that you can omit any leading zeros.)
In JavaScript, the syntax is \uXXXX. So, our example would be \u2290. (Note that the format is 4 hexadecimal characters.)
JavaScript TextOutput
let str = "\u2290"
document.write("My symbol: " + str)
My symbol: ⊐