HTML5 MathML
HTML5 MathML <mi> Tag
The <mi> tag represents an identifier - a variable, a constant, or a function name. Single-letter identifiers are rendered in italics by default, matching mathematical convention.
Definition and usage
The <mi> element holds a mathematical identifier. Browsers automatically italicise a single-character identifier (like x) but display multi-character names (like sin) upright. You can override the style with the mathvariant attribute, choosing values such as bold, italic, or double-struck.
Syntax
<mi mathvariant="normal">identifier</mi>Example
<math>
<mrow>
<mi>sin</mi>
<mo>⁡</mo>
<mi>x</mi>
</mrow>
</math>Here sin is a multi-letter identifier shown upright, while x is a single letter shown in italics. The invisible operator (⁡) marks function application between them.
ℹ️
The <mi> element is part of MathML Core and is supported by all modern browsers.