I looked for a reference.
http://stackoverflow.com/questions/156767/whats-the-differen...
"Summary"
"The general consensus seems to be that it's OK to use these terms interchangeably in a team environment. Except perhaps when you're defining the precise terminology; then you can also use 'formal argument/parameter' and 'actual argument/parameter' to disambiguate."
(You could also say something like "parameter value"... VC++ calls parameters "formal parameters" and arguments "actual parameters", for example.)