Here is a step by step guide on what it means when a lock sign next to the battery on an iPod Touch means and what to do about it.
iPod Touch Symbology
The iPod Touch, as well as the iPhone and iPad, are complicated devices in a sense because they bring in a whole lot of features and applications that seem to run on their own. At the same time, it seems easy to turn the features of the iPod Touch off and on without even realizing it. This can cause strange symbols to appear on the iPod Touch that you have no idea what to do about. One of the stranger questions that is asked is "What is the lock sign next to battery on ipod touch?" If you are wondering what the lock sign next to the battery on the iPod Touch then you are not alone and it indicates a very clear feature for the device.
What it Means
When you are wondering what the lock sign next to the battery on an iPod Touch is it is a symbol that indicates that the orientation of the iPod Touch has been locked. The orientation refers to the positioning of what is right side up or not on your iPod Touch. When you are holding the iPod Touch strait up it displays things with a thinner width and a taller height. When you turn it on its side it naturally re-orients the device so that the new top and bottom are in the correct position, except now it is very wide and short. If you find that there is a lock sign next to the battery on an iPod Touch then this means that the orientation is locked in the "right side up" position and when you turn it on its side it will not change.
How to Fix It
The lock sign next to the battery on an iPod Touch is there because it was assigned that way and you can easily take it off, but not in the normal iPod Touch settings area as you would with other iPod specifics. Instead, you do it at its multitask screen.
Double tap your iPod Touch's Home button to bring up the string of iPod Touch apps that have been left open. Scroll over to the left until you get to the last series of options, which will be centered around your iPod section's controls. To the left of this will be a square icon with a circle in it. This is the orientation button and you will just select it to turn off the orientation lock, and to remove the lock sign next to the battery on your iPod Touch. The text "Portrait Orientation Unlocked" will appear briefly below the icons to let you know that you have successfully removed the locked orientation setting. Now if you hit the Home button again and look next to your battery icon you will notice that no lock is there.
Source: Author's own experience.