Parameter vs Argument

Those two terms are often used interchangeably but we want to be precise when describing concepts like how parameters work and how argument are passed.

A parameter is the variable used during the method definition.

An argument is the actual value of this variable that gets passed to the method during method invocation.

def my_method(my_parameter)
  # Do stuff
end

my_argument = "I'm an argument!"
my_method(my_argument)

Mnemonic Tips

Glanned by yours truly around the Cyberspace:

  • Argument are Actual.
  • You define parameters and you make arguments.1
  • You can think of the parameter as a parking space and the argument as an automobile. Just as different automobiles can park in a parking space at different times, the calling code can pass a different argument to the same parameter every time that it calls the procedure.2