Which feature is not typically included in the definition of "hot" water?

The definition of "hot" water typically includes certain characteristics related to its temperature and potential effects. When considering the provided options, the concept of hot water is fundamentally connected to its capacity to reach certain temperatures that can induce burns and its general usability, rather than being limited to a specific function such as heating.

The option indicating that hot water is "used for heating purposes only" stands out because it inaccurately confines hot water to a single application. In reality, hot water is utilized in a variety of domestic activities beyond just heating, including bathing, cooking, cleaning, and sanitation. Therefore, this limitation does not accurately reflect the broader understanding of hot water and its applications in everyday life.

In contrast, the other choices provide specific thresholds and outcomes related to temperature that contribute to the conventional definition of hot water. These factors are commonly recognized in plumbing codes and safety guidelines regarding the use of hot water in various contexts. Thus, the distinct nature of the option related to a restricted use helps clarify why it does not fit within the standard definition of what constitutes "hot" water.