The multiplication sign (×), also known as the times sign or the dimension sign, is a mathematical symbol used to denote the operation of multiplication, which results in a product.

The symbol is also used in botany, in botanical hybrid names.

The form is properly a four-fold rotationally symmetric saltire. The multiplication sign × is similar to a lowercase X (x).

The earliest known use of the × symbol to indicate multiplication appears in an anonymous appendix to the 1618 edition of John Napier's Mirifici Logarithmorum Canonis Descriptio. This appendix has been attributed to William Oughtred, who used the same symbol in his 1631 algebra text, Clavis Mathematicae, stating:

Multiplication of species [i.e. unknowns] connects both proposed magnitudes with the symbol 'in' or ×: or ordinarily without the symbol if the magnitudes be denoted with one letter.

Other works have been identified in which crossed diagonals appear in diagrams involving multiplied numbers, such as Robert Recorde's The Ground of Arts and Oswald Schreckenfuchs's 1551 edition of Almagest, but these are not symbolizations.

In mathematics, the symbol × has a number of uses, including

In biology, the multiplication sign is used in a botanical hybrid name, for instance Ceanothus papillosus × impressus (a hybrid between C. papillosus and C. impressus) or Crocosmia × crocosmiiflora (a hybrid between two other species of Crocosmia). However, the communication of these hybrid names with a Latin letter "x" is common, especially when the actual "×" symbol is not readily available.