The electron domain geometry of H2O, or water, is tetrahedral. This is because the central oxygen atom has four electron domains around it: two bonding pairs (the hydrogen atoms) and two lone pairs of electrons.
In the VSEPR (Valence Shell Electron Pair Repulsion) theory, electron domains are regions where electrons are likely to be found. These domains repel each other and arrange themselves as far apart as possible to minimize repulsion. In the case of H2O, the four electron domains around the oxygen atom arrange themselves in a tetrahedral shape.
However, the molecular geometry of H2O is bent or angular because the lone pairs of electrons occupy more space than the bonding pairs, pushing the hydrogen atoms closer together. This results in a bond angle of approximately 104.5 degrees, which is less than the ideal tetrahedral angle of 109.5 degrees.