When Apple says 10hs of battery life, what do they mean?

http://www.apple.com/iphone/battery.html

iPad 2:

Testing conducted by Apple in February 2011 using preproduction iPad 2 units and software. Testing consisted of full battery discharge while performing each of the following tasks: video playback, audio playback, and Internet browsing using Wi-Fi or 3G. Video content was a repeated 2-hour 23-minute movie purchased from the iTunes Store. Audio content was a playlist of 358 unique songs, consisting of a combination of songs imported from CDs using iTunes (128-Kbps AAC encoding) and songs purchased from the iTunes Store (256-Kbps AAC encoding). Internet over Wi-Fi and 3G tests were conducted using dedicated web and mail servers, browsing snapshot versions of 20 popular web pages, and receiving mail once an hour. All settings were default except: Wi-Fi was associated with a network (except for Internet browsing over 3G); the Wi-Fi feature Ask to Join Networks and Auto-Brightness were turned off. Battery life depends on device settings, usage, and many other factors. Battery tests are conducted using specific iPad 2 units; actual results may vary.

The iPad's battery life is litteral. I'm sorry that you've been corrupted from all of the other tech companies that guarantee you that you can get 7 hours, when you really get about 2-3. The first iPad gave me 11 hours at tops, and at minimum, it might have given me 9:30 (with brightness a little bit higher, and playing games).

Now the MacBook Pros do stretch the truth a little bit, but they are improving those statistics starting with the MacBook Airs. I believe that their 5 hours (on MacBook Air) is pretty accurate.

I don't know how I did it but I managed to get 12 hours of battery life out of a single charge while watching a lot of videos (not all in HD) and playing possessor intensive games. So yeah you're pretty much guaranteed that it's going to be 10 hours of battery life.

it's probably the maximum time achieved by using the least powerful option, using all power saving features, screen down as dim as possible, system on complete idle with only the screen on, no wifi or anything like that.