n. the property of being rigid and resistant to pressure; not easily scratched; measured on Mohs scale
n. a quality of water that contains dissolved mineral salts that prevent soap from lathering
n. the quality of being difficult to do
n. 坚硬, 困难, 严厉, 勇气
[化] 硬度
1. The hardness of the diamond makes it very valuable.
钻石的硬度使它非常有价值。
2. You can test the hardness of the material using a special tool.
你可以使用特殊工具来测试材料的硬度。
3. The hardness of the water can affect the taste of the tea.
水的硬度会影响茶的味道。