To describe the bottom most portion of a door frame, you could use one of the following in English:
* Door sill: This is the most common term for the bottom part of a door frame.
* Threshold: This refers to the line that separates the inside from the outside of a doorway.
* Doorstop: This is the piece of wood or metal that prevents the door from swinging too far open.
You could also be more specific and use terms like:
* Bottom rail: This is the horizontal piece of wood that forms the bottom of the door frame.
* Base plate: This refers to the piece of wood that sits on the floor and supports the door frame.
Ultimately, the best English translation for "gadapa" depends on the specific context and what you are trying to describe.