Mathematical Bold Italic Small F 𝒇

Visual Description: This is a small Latin letter f rendered in bold italic. The strokes are thick and slanted, giving a sense of motion in mathematical text. It is compact enough to sit beside a variable or a subscript without crowding. In digital fonts, it stays clearly distinguished during dense equations.

Meaning & Usage: In math, a bold italic f often marks a function name or a special variable. It helps separate function definitions from constants. In typesetting, the weight and angle cue emphasis, enabling quick recognition in long formulas. Calculators and formula editors use this style to highlight operations and mappings.

Historical Background: Historically, bold italic styles grew as printing moved from metal type to digital fonts. Designers chose combined weight and slant to keep emphasis without losing clarity in tight math lines. Across education and publishing, the bold italic f became a visual cue for function labels and named variables.

Practical Use: In practice, bold italic f marks a function in many formulas. It appears in calculators as the function label in the input area and in formula views. UI tools may provide quick controls to apply f to arguments, switch modes, or compare f(x) results with A & B values.

See our category page for related symbols.

Look‑alikes: f (U+66).

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