One story says it got that meaning from the custom of throwing boiling water down on enemies attacking a castle.

VOA: special.2009.05.10

If I get you down to a cluster of about 30 water molecules, the boiling point is a function of the size of the water droplet.

如果对于一个由30个水分子,组成的簇，沸点是,水珠尺寸的函数。

麻省理工公开课 - 固态化学导论课程节选