Tynker has a particular layout with the blocks on the left editor in the middle and output on the right which word best describes this screen layout

The word that best describes this screen layout is a traditional or standard layout.

The screen layout of Tynker can be described as a "three-panel layout" or a "paneled interface".

The screen layout you are referring to in Tynker can be best described as a "three-panel layout" or a "split-screen layout."