Who discovered water vapor?

Water vapor was not "discovered" by a single individual, as it is a natural component of the atmosphere. However, early studies of gases and their properties, including those of water vapor, date back to the work of scientists like Robert Boyle in the 17th century and Joseph Louis Gay-Lussac in the early 19th century. Their experiments helped to elucidate the behavior of gases, including water vapor, within the context of gas laws.