The Hebrew word mayim means “water,” but its form is less simple than its meaning. It looks plural, even though it usually refers to a single substance.
Mayim is not alone. Hebrew has other words like this, including panim, “face,” and shamayim, “heaven” or “sky.” All appear in a plural form, even though they are not really plural in the usual sense. We do not usually think of water, sky, or face as multiple units.
Some have tried to connect mayim to the division between the upper waters and lower waters in the Creation story. That is an appealing idea, but it does not seem to have linguistic support.
Other forms of the word point in a different direction. In the construct form, mayim becomes mei, and in post-biblical Hebrew we even find meimot, a more clearly plural form.
The word may also have left its mark beyond grammar. The Hebrew letter mem is associated with water, and its name may be linked to mayim. In ancient scripts, the letter was often drawn with a wavy or zigzag shape, fitting for a word connected to water. That same letter eventually became the Greek mu, then the Latin M, and finally the English m. The form changed over thousands of years, but something of the original wave still remains.
So, a word as basic as mayim may have left its mark not only on Hebrew vocabulary, but on the shape of the alphabet itself.