sub·tropical I. adjective alsosub·tropic\“+\ Etymology: International Scientific Vocabulary sub- + tropical or tropic 1.: nearly tropical : of, relating to, or being the regions bordering on the tropical zone 2.of a plant: requiring climatic conditions typical of subtropical regions to survive < even near the equator vegetation at 5000 feet is subtropical rather than tropical > II. noun : a plant requiring a subtropical environment to thrive