Mathematical Italic Capital O 𝑂

Visual Description: The symbol is a bold, rounded circle with a light italic slant. It resembles a standard O but is tilted to signal a variable or constant. In math software, it appears as a stylized letter that fits compact formulas and calculators. The line quality stays clear at small sizes.

Meaning & Usage: This capital O stands for a variable or a set in math and science. In equations it often marks an unknown or a general object. It helps distinguish text from numeric values. In UI, users select it as a token in quick calculators or expression builders for comparisons.

Historical Background: The symbol is part of a family of mathematical alphanumeric symbols found in typeface collections. It was designed to provide a distinct italic form for variables while keeping compatibility with Latin letters. The idea spread through fonts and math editors, enabling consistent notation across tools.

Practical Use: In practice, you type this O in formulas to denote a variable, a matrix label, or a placeholder. In calculators, it serves as a token in quick UI controls for operations or comparisons. It helps keep expressions clear when switching between plain text and formatted math.

See our category page for related symbols.

Look‑alikes: O (U+4F).

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