If you had gone through the Play store you may notice that their are changes in the category. That is because Google has changed the chromecast category to Google Cast simply. Google is also making some changes to the category so that users might be able to better understand the differences between the Chromecast itself and the feature that makes it possible to stream media content to the device.
This does make sense, as Google Cast is the technology behind the streaming, and more devices are grabbing the capability to use it, so in the name of unification, it just makes sense for Google to call everything by one standard name across all devices. As the Play Store update has begun rolling out today those who have already gotten it should see the name change, and those who haven’t quite yet received the update will most likely still see the category listed as Chromecast.