aquation / equation [ɪˈkweɪʒən]
aquation – n. – Chem., the replacement of a coordinated atom or group on a coordination complex by water
equation – n. – 1. a statement that indicates that two mathematical expressions have the same value and usually shown by the equals sign (=); 2. a symbolic writing of a chemical reaction; 3. the action of making two or more things identical in some parameter