Double Nested Less-Than HTML entity &LessLess;

&LessLess; is the HTML entity for Double Nested Less-Than ⪡ (U+2AA1). Copy ⪡, ⪡ and the CSS, JavaScript, Python and URL escapes.

Entity: &LessLess;
Code point: U+2AA1
Unicode name: DOUBLE NESTED LESS-THAN
Block: Supplemental Mathematical Operators
Category: Math symbol (Sm)
Since: Unicode 3.2
Defined in: HTML5

Codes to copy

HTML named	`&LessLess;`Works in HTML; in XML only & < > " ' are predefined.
HTML decimal	`⪡`Works in HTML and XML.
HTML hex	`⪡`Works in HTML and XML.
CSS	`content: "\2AA1";`In a stylesheet, for ::before and ::after.
JavaScript	`"\u2AA1"`Also valid in JSON.
Python	`"\u2aa1"`Python 3 string literal.
Python by name	`"\N{DOUBLE NESTED LESS-THAN}"`Readable alternative using the Unicode name.
URL	`%E2%AA%A1`Percent-encoded UTF-8 bytes, for a path or query value.
UTF-8 bytes	`E2 AA A1`3 bytes.
UTF-16	`2AA1`1 code unit, which is what JavaScript length counts.

When to use it

&LessLess; writes U+2AA1 (Double Nested Less-Than), a maths symbol from the Unicode Supplemental Mathematical Operators block, encoded since Unicode 3.2. Specialist notation like this usually belongs in MathML, which positions it correctly; the entity is for occasional use in running text.

The name comes from the HTML5 list (much of it shared with MathML), so it works in every current browser but not in XML or XHTML served as XML, where the numeric reference is the safe choice.

More advanced maths and arrows

All advanced maths and arrows · Every HTML entity · Encode or decode text

Source: the WHATWG HTML Standard list of named character references and the Unicode Character Database (Unicode 18.0).