aromatic annual or perennial herbs and shrubs
"The botanist carefully cataloged the various tobacco species, noting that each is an aromatic herb or shrub grown for its leaves."
Any plant of the genus Nicotiana.
"The botanist explained that while tobacco is commonly used for smoking, it refers specifically to any plant belonging to the genus Nicotiana."
In plain English: Tobacco is a plant that people often smoke or chew, which is harmful to your health.
"He keeps a pack of tobacco in his desk drawer for when he wants to chew."
To indulge in tobacco; to smoke.
"He decided not to join us outside because he was trying to quit tobacco."
In plain English: To smoke tobacco is to burn it and inhale the smoke into your lungs.
"The company decided not to tobacco its competitors by lowering prices unfairly."
Usage: Tobacco as a verb means to consume or inhale the substance, typically by smoking it. This usage is now archaic and rarely appears in modern conversation compared to simply saying someone smokes.
The word tobacco entered English in 1588 from the Spanish tabaco. Its ultimate origin is uncertain, possibly deriving from an Arabic term for a specific plant or from Caribbean languages where it meant "roll of leaves" or "smoking pipe."