The term 'containing water' can be described by three crossword solutions: HYDRATE (7 letters), HYDROUS (7 letters), and AQUEOUS (7 letters). HYDRATE is a verb meaning to provide an organism with enough water, while HYDROUS and AQUEOUS are both adjectives meaning containing or consisting of water. HYDROUS specifically refers to a substance that contains water molecules in its chemical structure, while AQUEOUS refers to a solution that has been dissolved in water.