noun
home screen
Refers to the main screen of a smartphone, tablet, or similar device, where app icons and widgets are displayed.
スマホのホーム画面に天気予報のウィジェットを追加した。
I added a weather forecast widget to my smartphone's home screen.
ロック画面 is the lock screen shown before unlocking the device, while ホーム画面 is the main screen after unlocking.
Compound of ホーム (from English 'home') and 画面 (screen).