hard water: water that contains mineral salts (as calcium and magnesium ions) that limit the formation of lather with soap
water: 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
phonetics: the branch of acoustics concerned with speech processes including its production and perception and acoustic analysis