Wiktionary
main earth
n. (context fox hunting English) A fox's primary lair. (from 19th c.)
Usage examples of "main earth".
It would soon be back at the main Earth Naval Base, totally free of the gases that had destroyed all organisms.
No sign of Martha or Lisketter there, since they took them into the big place on the main earth mound.
The arrival of the Ix Mentat and its two juniors at the Catteni main Earth spaceport in Texas, near what had been Houston, caused major security problems.