What does the house icon mean on my Lyric?

The house icon lets you put your thermostat into Away mode with a touch. Away mode allows you to change your temperature settings so you don't use so much energy while no one is at home. If the house button on your thermostat is glowing green, you are currently in Away mode. Push the button to return from away mode.
If you wish to turn on Away mode:
From the Lyric app
Select your preferred location, then tap a thermostat. Tap the house to tell your Lyric how long you will be away for. You can set the Lyric to Away mode for up to 24 hours. Then hit Save to put it into Away mode. To change your Away settings, tap the gear icon from the thermostat screen, then tap Away Settings to either allow Honeywell to maximize your energy savings or to manually set your Away temperatures. These temperatures will be your Away settings until you choose to change them again.
From the thermostat
Press the house button on the right of the thermostat. This is a one-touch button to put the thermostat into its energy saving Away mode. You can turn the dial to adjust your expected time away between 1 and 8 hours; if you do not, the thermostat will default to your most recent duration Away and enter away mode.