The term 'Taj Mahal Topper' refers to the large marble DOME that sits atop the Taj Mahal in Agra, India. The DOME is one of the most recognizable features of the Taj Mahal and is often referred to as the 'Taj Mahal Topper'. The crossword solution for this term is 'DOME', which is a four-letter word. The DOME is an impressive structure, measuring 35 meters in height and 50 meters in diameter. It is made of white marble and is decorated with intricate carvings and inlaid semi-precious stones.