Mathematical Left Angle Bracket

The Mathematical Left Angle Bracket at U+27E8 is a mathematical delimiter used as the opening half of an angle-bracket pair. It belongs to the Miscellaneous Mathematical Symbols-A block and is meant for notation where the bracket shape carries mathematical meaning rather than ordinary punctuation. In mathematics, it most often appears with its matching right bracket to enclose structured objects. Common examples include inner products such as ⟨u, v⟩ in linear algebra, ordered pairs or tuples in some texts, and generated subgroups such as ⟨S⟩ in abstract algebra. In quantum mechanics, it is used in bra-ket notation: a bra is written like ⟨ψ| and pairs with a ket such as |φ⟩ to express states and inner products. It also appears in formal language theory and linguistics-style notation, where angle brackets may surround sequences, phonetic or orthographic forms, or metavariables depending on the convention. It should not be confused with the less-than sign, the single guillemet, or the ordinary angle bracket characters used in markup; those may look similar but have different typographic roles and text identities.