Data transferred in the background, i.e. without explicitly being triggered. This usually includes things like synchronizing your calendar and contact data.
What are "background data"?
One could talk about "foreground data" when referring to explicitly triggered downloads, or webpages retrieved interactively using a browser. Opposed to that, several services transfer data in the brackground, without the user explicitly triggering this. Examples include, but are not restricted, to...
- synchronizing your contacts and calendars with Google services
- updating location information, e.g. with Latitude
- Google Play (and other apps) checking for updates
Some apps, including the Google-Play app, require background-date to be enabled. Depending on device, Android version, and ROM, the corresponding setting might be found in different places:
- Settings→Accounts & Sync
- Menu→Settings→Battery data manager→Delivery
With Google Play and your contacts/calendar sync depending on background data being enabled, in most cases it's not a good idea to completely disable them -- even though some misbehaving apps might use it too much. A How-To shows what you can do instead to gain control (at least with Android 4.0 and higher).
- data-connection: for issues with your mobile data connection
- data-plan: a fixed amount of data included with your regular fee
- data-traffic: amount of data transferred. Use this for questions/issues like finding out which app is eating up your data plan.
- wi-fi: using your home WiFi network
- bluetooth: another wireless technology, but limited to short distances.
- usb: this can also be used to transfer data, but is not wireless.
- mobile-data: transferring data via your mobile data connection (2g/3g/4g)