doesnt "maa" also mean "what"? e.g.: maa ismak ya ustadha?
they're spelt differently - ما as in "maa ismuk" and ماء as in water (note: ma for water has a more shorter ending because of the hamza)
How do you say,,,,This water is cold? It stands to reason that هٰذا refers to the water. This water and not this cold....
This water is cold : هذا الماء بارد
.لاء sounds ماء