What is "untrod"

Usage examples of "untrod".

And soon the catacomb divided and redivided before him, so that he must choose his way at random, not knowing whether it would lead him back to Ummaos or into the untrod depths.

All were ungovernably excited by the novelty of their position, and were aware of a terrible disquietude, a wild nervousness due to the shock of being plunged among alien atmospheric and geologic forces, the magnetic emanations of a soil untrod by human foot.