About

The number of argument in a function signature is called the arity

Articles Related

List

• 0-ary - Function - Nilary / Nullary - 0 argument
• 1-ary - Function - Unary - 1 argument
• 2-ary - Function - Binary Function/Operation - two arguments
• 3-ary - Ternary - three arguments. Example:
  • Language - Conditional operator (ternary)
  • three-valued logic (true, false, unknown)

Documentation / Reference

• More wiki/Arity