Mathematical Bold Fraktur Capital K 𝕶

Visual Description: The character appears as a bold Fraktur K, with heavy strokes and sharp, angular serifs. It keeps the decorative blackletter look while staying legible in math text. The stroke contrast and tight curves give it a distinct, formal presence among standard Latin letters and symbols.

Meaning & Usage: This K does not have a fixed numeric meaning. In formulas it marks a special object, a named constant, or a labeled set chosen for emphasis. It helps readers distinguish symbols from ordinary variables. In calculators or editors, it signals a stylistic choice for quick recognition.

Historical Background: Fraktur styles come from older German blackletter typography and from the rise of distinct typefaces in print. In math, bold Fraktur was adopted to provide a formal, high-contrast alternative to plain letters. It offered a way to separate named objects from ordinary variables without changing meaning.

Practical Use: In digital math work, apply a bold Fraktur style to indicate a named object or a special set. Use a font toggle, a font family option, or a CSS class to render K this way. In LaTeX or math editors, choose the Fraktur family or a bold option for formulas and comparisons.

See our category page for related symbols.

Look‑alikes: K (U+4B).

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