Wiktionary
n. 1 (context organic compound English) The organic derivative of stannane ''tributylstannane'' 2 (context organic chemistry English) Any of many derivatives of this compound that are used as biocides
Wikipedia
Tributyltin (TBT) is an umbrella term for a class of organotin compounds which contain the (CH)Sn group, with a prominent example being tributyltin oxide. For 40 years TBT was used as a biocide in anti-fouling paint, commonly known as bottom paint, which was applied to the hulls of ocean going vessles. Bottom paint improves ship performance and durability as it reduces the rate of biofouling, which is the growth of organisms on the ship's hull. Although such paints are effective, the TBT slowly leaches out into the marine environment where it is highly toxic to a wide range of organisms. TBT pollution is of serious concern as it has led to collapse of whole populations of organisms.