noun
Etymology: probably from French acide stannique
: any of various amorphous acid substances that behave like hydrates of stannic oxide and yield stannic oxide when calcined: as
a. : a highly hydrated substance obtainable as a gelatinous precipitate by hydrolysis of stannic chloride by alkali or excess water and forming salts with more alkali — called also alpha-stannic acid
b. : a less highly hydrated substance obtainable as a powder by heating or drying alpha-stannic acid — called also beta-stannic acid