sub-screen; pop-up window; child window
Computing term for a secondary window or screen that appears within or alongside a main interface, such as a pop-up, dialog, or inset video feed.
To change the settings, please open the sub-screen.
During a video call, you can share materials in a pop-up window.
Compound of 子 (こ, 'child') and 画面 (がめん, 'screen'), literally 'child screen'. A straightforward technical term formed from existing kanji.