The term HT, which is an abbreviation for Height, can be solved by the crossword solutions ABOVE SEA LEVEL and ALT (3 letters) and ELEV (4 letters). The term Height is used to describe the vertical distance of an object or point in relation to SEA LEVEL. SEA LEVEL is the average height of the surface of the ocean and is used as a reference point for measuring elevation. Altitude is the height of an object or point ABOVE SEA LEVEL, while elevation is the height of an object or point ABOVE the ground.