This is the 377th most frequent Czech word.
vody
"Vody" means "water" in the genitive or accusative case, or "waters" in plural form.
Here, 'vody' is the genitive singular form of the noun 'voda', used to indicate possession or to specify the contents of the glass.
Potřebuju sklenici vody.
I need a glass of water.
Here, 'vody' is the genitive singular form, describing the specific type or attribute of water.
Bojím se hluboké vody.
I am afraid of deep water.
In this context, 'vody' is also in the genitive singular because it specifies the ownership or relation of the quality to the water in the river.