The ⊂ (Subset Of) Symbol: Meaning, Math & How to Type It

The ⊂ symbol, officially named "Subset Of," is a fundamental mathematical operator used in set theory to indicate that one set is entirely contained within another. For example, if set A contains only elements that are also found in set B, mathematicians write A ⊂ B. Think of it like nested folders on your computer—the inner folder is a subset of the outer one.

Introduced during the development of set theory in the late 19th and early 20th centuries, this symbol was popularized by mathematicians like Giuseppe Peano and Bertrand Russell. In the Unicode Standard, ⊂ is assigned the code point U+2282 and lives comfortably within the Mathematical Operators block.

While you will mostly find ⊂ in academic papers, textbooks, and scientific journals, it occasionally makes its way into everyday digital spaces. In programming, developers rarely use the symbol directly in source code due to standard keyboard limitations, but it appears frequently in documentation, data science algorithms, and LaTeX formatting. Outside of math, internet users sometimes get creative with ⊂, using it in text-based ASCII art or kaomoji to represent a sideways mouth, a cup, or a magnet.

Typing the ⊂ symbol varies depending on your device. On Windows, you can type it in Microsoft Word by entering 2282 followed by Alt + X, or by holding down the Alt key and typing 8834 on your numeric keypad. On a Mac, the easiest method is bringing up the Character Viewer (Control + Command + Space) and searching for "subset." Web developers can easily drop it into a page using the HTML entity ⊂ or ⊂, while LaTeX users rely on the \subset command.

If you are diving deep into mathematical typography, you will quickly encounter related symbols that look similar but carry different meanings. The ⊃ symbol (Superset Of, U+2283) is the exact opposite, indicating that the first set contains the second. The ⊆ symbol (Subset of or Equal To, U+2286) allows for the possibility that both sets are identical, whereas ⊂ is often used to represent a "proper" or "strict" subset where the sets cannot be exactly the same. Finally, ⊄ (Not a Subset Of, U+2284) clearly states that the first set contains elements outside the second.