Sentence:  Six hundred and forty acres , the old man back in St. Louis had said ; good grass , good <WSD>water</WSD> . 
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