The central atom in water (H₂O) is oxygen. Here's how to determine its hybridization:

1. Count the number of electron groups around the central atom: Oxygen has two single bonds to hydrogen atoms and two lone pairs of electrons. This gives a total of four electron groups.

2. Relate the number of electron groups to the hybridization:

- Four electron groups correspond to sp³ hybridization.

Therefore, the hybridization of the central oxygen atom in water is sp³.