a. (Chem.) Pertaining to, or containing, tin; specifically, designating those compounds in which the element has a lower valence as contrasted with stannic compounds. [ 1913 Webster ]

Stannous chloride (Chem.), a white crystalline substance, SnCl2.(H2O)2, obtained by dissolving tin in hydrochloric acid. It is used as a mordant in dyeing. [ 1913 Webster ]