泰姬 in Chinese is shorthand for
泰姬陵 (Tàijīlíng, the Taj Mahal) — the white marble mausoleum in Agra built by Mughal emperor
沙贾汗 (Shah Jahan) for his wife
慕塔兹·
玛哈尔 (Mumtaz Mahal), who died in 1631 in childbirth. Her title 'Mumtaz Mahal' literally means 'the chosen one of the palace'; the 'Taj' part means 'crown' in Persian. So
泰姬陵 = 'Crown Tomb', and
泰姬 alone usually evokes both the empress and the monument.