Mathematical Bold Capital X 𝐗

Visual Description: A bold capital X is drawn with thick, uniform strokes that stand out on the page. The letter is larger and darker than surrounding text. The shape is simple, with two crossing diagonals forming a crisp mark. In mathematical notation, it flags a primary variable or a vector.

Meaning & Usage: In many contexts, a bold X signals a vector or a distinguished variable, rather than a scalar. It helps separate X from plain x. In formulas, bold X participates in operations like addition, subtraction, or products when paired with other vectors. In interfaces, X marks a target for comparisons or selections.

Historical Background: The use of bold letters for vectors grew with print and later digital typesetting. It is not tied to a single inventor or era. Across disciplines, bold X and other bold capitals were adopted to distinguish quantities, while lowercase letters remain common for scalars and coordinates.

Practical Use: In everyday math and science work, bold X helps keep vector notation clear in dense equations. Calculators and graphing tools often offer a vector mode where X is a labeled entry. Quick UI controls let you set X, compare vectors, or perform dot products and matrix multiplications.

See our category page for related symbols.

Look‑alikes: X (U+58).

Need styled alternatives? Try the Fancy Text tool.