The process of losing water by leaves is known as transpiration.

More on Transpiration:
Transpiration is a crucial process for plants, as it helps to regulate the water balance within their tissues.

Transpiration has important ecological and environmental implications. For example, the release of water vapour into the atmosphere during transpiration contributes to the formation of clouds and precipitation, which helps to sustain ecosystems and support agriculture. Additionally, transpiration can affect local climate patterns, such as by increasing the humidity in forested areas and reducing the amount of heat absorbed by the ground.

Overall, transpiration is a complex and multifaceted process that plays a critical role in the survival and success of plants, as well as in the functioning of ecosystems and the global water cycle.