What is the name given to the temperature at which vapor at 100% humidity starts to condense into a liquid?

The temperature at which vapor at 100% humidity begins to condense into a liquid is known as the dew point. This term specifically describes the temperature at which air becomes saturated with moisture, meaning it cannot hold additional water vapor, leading to condensation. Understanding the dew point is crucial in fields like meteorology and air conditioning, as it indicates when humidity levels are high enough for condensation to occur, which can affect comfort levels and weather patterns.

In contrast, terms like the boiling point refer to the temperature at which a liquid turns into vapor, while the freezing point is related to when a liquid becomes solid. The condensation point might seem similar, but it is not the standard terminology used in relation to humidity and phase changes in vapor. Thus, the dew point is correctly identified as the specific term that defines the point of condensation from vapor in humid conditions.