COM Stands for:

Component Object Modal

It is a binary standard to which components (Like VB ActiveX Dll's And ActiveX Controls) are created..

So it allows you to develop components in any COM Compliant language, which can then be used by any COM Compliant language... EG You can write a Component in C++ and use it in VB.

COM also specifies some rules regarding the Interface of a component (Its methods and properties).

I wouldnt worry too much about your interview, just keep in mind that if the ymention COM components they are probably refrering to ActiveX Dlls, Controls etc...

Hope this helps, Good Luck!