Meanings of frontmost in English

I usually get on at the frontmost door of the second car.

The menu bar is where the frontmost application's menus appear.

The first is the Z-fold, where the frontmost panel stays parallel to the ground, coming up like a cobra rising to strike.

Then they hobbled the kanks together, frontmost legs of one to the hindmost of another, and unlashed the harness from the soldier-kank's back.

"Very well." Stratton had the automaton follow the two of them back to the frontmost of the complex of connected buildings that was Coade Manufactory.