no
There are various types of Nexus devices, but the Nexus 7 is part of that same family.
The Nexus 7 is an Android Tablet made by Google. It has a screen size of 7 inches.
Yes, you can use multiple Google accounts.
Yes, it has Google Play.
No, you will have to download a movie to a Nexus 7 tablet on your own.
It is a tablet.
Yes, it is available in the Google Play store.
Not really, unless you count the Google and Nexus branding as "ads".
On the surface, it may not appear that you can make calls on a Nexus 7. However, you can do so if you use VoIP software (Voice over IP) such as Google Voice.
Yes you can.
The 7 in Google Nexus 7 has not been openly mentioned to stand for anything. However, the recent Nexus tablet iterations (and to some degree, the phone as well) appear to refer to screen size. Both generations of the Nexus 7 have 7 inch and 7.02 inch screens respectively. The Nexus 10 has a 10.1 inch screen. The Nexus 4 has a 4.7 inch screen. The rumored Nexus 5 is supposed to have a 5 inch (or larger) screen.