What is the chemical formula for water?

H2O is the chemical formula for water.

It can be separted into

H2 = 2 hydrogen atoms

O = 1 oxygen atom .

Structurally they are arranged as H-O-H .

Water is the universal name , but reading the formula it you could describe it as :-

Hydrogen monoxide

Dihydrogen oxide

Hydrogen oxide

Dihydrogen monoxide.

However , nobody does, unless you wish to play 'silly tricks'.