n.1 an exchange of views, esp. a contentious or prolonged one.
2 (often foll. by for, against) a reason advanced; a reasoning process (an argument for abolition).
3 a summary of the subject-matter or line of reasoning of a book.
4 Math. an independent variable determining the value of a function.
Etymology: ME f. OF f. L argumentum f. arguere (as ARGUE, -MENT)