There is no such idiom.
Yu, pronounced yù, comes from Wuyin Jiyun. Its original meaning is precious treasure, which also refers to hard metal. Characters used for names.
radical: cheng.
total strokes: 1.
structure: left and right structure.
synonymous: treasure, jade and solid gold.
reading and writing in the order of strokes: leaving horizontal and vertical directions and checking horizontal and vertical points.
related words
1. Shi Yu? [shiyī]
Shiyu is generally known as a man who is as charming as a treasure, and also refers to a pure scholar and a brilliant scholar.
2. Ming Yu? [míng yù] Meiyu, very shiny, will become the atmosphere.