Underground plane Synonyms

Underground replaced

Definitions for Underground


  • (adjective) undertaken or done so as to escape being observed or known by others
  • (adjective) being, situated, or operating beneath the surface of the earth
  • (noun) a secret organization in a conquered country fighting against enemy forces

Synonyms for phrase

UP abbreviation

UP is an abbreviation for Underground Plane
What does UP stand for?
UP stands for "Underground Plane"

Plane replaced

Definitions for Plane


  • (adjective) having a surface without bends, breaks, or irregularities
  • (noun) a vehicle for traveling through the air that has fixed wings for lift
  • (verb) to make free from breaks, curves, or bumps