Sentence:  The seemingly quiet ocean had crashed a wall of <WSD>water</WSD> from 10 to 100 feet high upon beaches crowded with bathers , drowning thousands of them and flattening villages along the shore . 
Meaning of the word marked with <WSD> tags:  binary compound that occurs at room temperature as a clear colorless odorless tasteless liquid; freezes into ice below 0 degrees centigrade and boils above 100 degrees centigrade; widely used as a solvent