Nabla ∇

The Nabla character (∇) is a standard HTML entity defined in the HTML specification. In HTML source code, it can be written using the named entity reference ∇, the decimal numeric character reference ∇, or the hexadecimal numeric reference ∇. The character is assigned Unicode code point U+2207 in the Universal Character Set.

The nabla symbol (inverted triangle, also called del) is a vector differential operator used in mathematics and physics. It represents gradient, divergence, curl, and Laplacian operations depending on context. The symbol is named after an ancient Hebrew harp with a similar triangular shape.

Mathematical HTML entities enable web authors to display proper mathematical notation without relying on images or specialized rendering libraries like MathJax or KaTeX. While complex equations and multi-line formulas may still benefit from dedicated math typesetting tools, individual symbols expressed as HTML entities render quickly, remain accessible to screen readers, and can be styled with CSS just like regular text content.

When deciding how to encode the Nabla character in your HTML documents, the named entity ∇ is generally the most readable choice for developers reviewing or maintaining source code. The decimal form ∇ and hexadecimal form ∇ are equally valid alternatives that work in contexts where named entities may not be supported, or when generating HTML output programmatically from server-side code. All three representations produce identical visual output in every modern web browser.

Use the nabla symbol in vector calculus expressions for gradient (∇f), divergence (∇·F), curl (∇×F), and Laplacian (∇²f) operations. It is essential for electromagnetic theory, fluid dynamics, and any physics or engineering content involving field equations.