Argument

An argument is a value supplied to a routine, like:

routine RoutineName(argument1,argument2)

Kent’s own words

Truth is, arguments are just the first local variables in a routine, so

   routine MyRoutine(first_arg)
   {
        ...

is the same as

   routine MyRoutine
   {
        local first_arg
        ...

since either can be called as MyRoutine(value) and have first_arg = value.

So, arguments are local variables, but it is convenient to use their separate syntax as it makes the routine easier to read.