In mathematics a Steinberg symbol is a pairing function which generalises the Hilbert symbol and plays a role in the algebraic K-theory of fields. It is named after mathematician Robert Steinberg. For a field F we define a Steinberg symbol (or simply a symbol) to be a function, where G is an abelian group, written multiplicatively, such that * is bimultiplicative; * if then . The symbols on F derive from a "universal" symbol, which may be regarded as taking values in . By a theorem of Matsumoto, this group is and is part of the Milnor K-theory for a field.