The crossword solution for the term 'Trough Spot' is STY. A STY is a small, painful lump that forms on the eyelid due to an infection of the oil glands in the eyelid. It is usually filled with pus and can cause redness, swelling, and irritation. Sties are usually caused by bacteria, but they can also be caused by allergies or other irritants. Treatment typically involves antibiotics or warm compresses.