J (disambiguation)

J is the tenth letter of the Latin alphabet.

J may also refer to:

Mathematics

• J, symbol used to denote the Bessel function
• j, used as the symbol for the imaginary unit (${\displaystyle {\sqrt {-1}}}$) in fields where i is used for a different purpose (such as electrical current)
• j, a number with the property j 2 = +1, used in the definition of the split-complex numbers
• j, the second imaginary unit of a quaternion
• j, an index variable in a matrix
• The j-invariant, a modular function

Film and television

• Agent J, a character in the Men in Black films portrayed by Will Smith
• J, an antagonist in Bobobo
• Kamen Rider J, a Japanese movie