>>If you mean C++ when you can inherit from multiple classes, then you got the term correctly.
>
>So Polymorphism it is. Is that correct?

No. I meant that it is called 'multiple inheritance'. I don't believe there is a better term. Also, as Craig said, it is only available in C++, but not in C#/VB.NET

I am not exactly sure which other languages allow to inherit from multiple classes - a quick google search should help to answer.

Well,

http://en.wikipedia.org/wiki/Single_inheritance#Single_inheritance

Quote:

Multiple inheritance is a feature of some object-oriented computer programming languages in which a class can inherit behaviors and features from more than one superclass.

Languages that support multiple inheritance include: C++, Common Lisp (via CLOS), EuLisp (via The EuLisp Object System TELOS), Curl, Dylan, Eiffel, Logtalk, Object REXX, Scala (via the use of mixin classes), OCaml, Perl, Perl 6, Python, and Tcl (via Incremental Tcl).[1]