Water is the root word for many other words.
Old English wter, from Proto-Germanic *watr-, comes from Old Saxon watar, Old Frisian wetir, Dutch water, and Old High German wazzar.
The meaning of keeping one's head above water is recorded from 1742.Water cooler, water polo, and water torture were recorded.The root words for water are *ap- and *wed-.The first (preserved in Sanskrit apah as well as Punjab and julep) was referred to as animate, meaning water as a living force.The same might be true of fire.
Old English says "moisten, irrigate, supply water to; lead (cattle) to water;" from water.The meaning is from late 14c.Usually it is as water down.Water "urinate" can be made from early 15c.Watered is related to watering.
It is a measure of the quality of a diamond from water.