Heroine of 红楼梦, the orphaned, sickly cousin who loves 贾宝玉 and dies of grief as he is married to another. She writes the poem 葬花吟, and calling someone "a Lin Daiyu" means they are oversensitive and tearful.
In the novel's frame story she was a crimson pearl plant, 绛珠仙草, watered daily with dew by the being who became Baoyu, and she is born to repay him with a lifetime of tears. Their bond is the 木石前盟, 'old pledge of wood and stone'.
culture
黛 is a blue-black pigment once used to paint eyebrows. When they first meet, Baoyu gives her the courtesy name 颦颦, 'Frowner', for her slightly knitted brows, citing a book on this pigment that his sister Tanchun suspects he made up.