Pronunciation: (tu-bak'ō),[key] —n., —pl.-cos, -coes. 1. any of several plants belonging to the genus Nicotiana, of the nightshade family, esp. one of those species, as N. tabacum, whose leaves are prepared for smoking or chewing or as snuff.
2. the prepared leaves, as used in cigarettes, cigars, and pipes.
3. any product or products made from such leaves.
4. any of various similar plants of other genera.