Y  This is the terminal for cooling or air conditioning and goes to the compressor relay. Typically a thermostat wire pull is made to the air handler on split systems and then this wire is spliced for the separate wire pull which is made to the condenser.
profound (comparative more profound, superlative most profound) 1  Descending far below the surface; opening or reaching to great depth; deep. 2  Very deep; very serious. 3  Intellectually deep; entering far into subjects; reaching to the bottom of a matter, or of a branch of learning; thorough a profound investigationâ. a profound scholarâ.
1. deep, sagacious. 1. shallow, superficial. 1  penetrating or entering deeply into subjects of thought or knowledge; having deep insight or understanding:a profound thinker. 2  originating in or penetrating to the depths of one's being; profound grief.