var element represents a variable. This could be an actual variable in a mathematical expression or programming context, or it could just be a term used as a placeholder in prose.
In the paragraph below, the letter "n" is being used as a variable in prose:
<p>If there are <var>n</var> pipes leading to the ice cream factory then I expect at <em>least</em> <var>n</var> flavors of ice cream to be available for purchase!</p>
For mathematics, in particular for anything beyond the simplest of expressions, MathML is more appropriate. However, the
var element can still be used to refer to specific variables that are then mentioned in MathML expressions.
In this example, an equation is shown, with a legend that references the variables in the equation. The expression itself is marked up with MathML, but the variables are mentioned in the figure's legend using
<figure> <math> <mi>a</mi> <mo>=</mo> <msqrt> <msup><mi>b</mi><mn>2</mn></msup> <mi>+</mi> <msup><mi>c</mi><mn>2</mn></msup> </msqrt> </math> <figcaption> Using Pythagoras' theorem to solve for the hypotenuse <var>a</var> of a triangle with sides <var>b</var> and <var>c</var> </figcaption> </figure>