Homonym: hard (Difficult)
The term "hard" refers to a material's resistance to deformation or scratching. For example, substances like diamond and steel are considered hard because they can withstand significant force without changing shape. Hardness is often measured using scales such as the Mohs scale, which ranks minerals based on their ability to scratch one another.
In a broader context, "hard" can describe tasks or challenges that require significant effort or skill. For instance, learning a new language or solving complex math problems can be seen as hard due to the mental effort involved. This usage highlights the difficulty associated with certain activities or situations.