https://realpython.com/python-gui-tkinter/
The foundational element of a Tkinter GUI is the 'window'. Windows are the containers in which all other GUI elements live. These other GUI elements, such as text boxes, labels, and buttons, are known as 'widgets'. Widgets are contained inside of windows.
Each widget in Tkinter is defined by a class.
+--------------+-------------------------------------------------------------+ | Widget Class | Description | +==============+=============================================================+ | Label | A widget used to display text or images on the screen. | +--------------+-------------------------------------------------------------+ | Button | A button that can contain text and can perform | | | an action when clicked. | +--------------+-------------------------------------------------------------+ | Entry | A text entry widget that allows only a single line of text. | +--------------+-------------------------------------------------------------+ | Text | A text entry widget that allows multiline text entry. | +--------------+-------------------------------------------------------------+ | Frame | A rectangular region used to group related widgets | | | or provide padding between widgets. | +--------------+-------------------------------------------------------------+