Belladonna is a plant that has been used for centuries in medicine and as a poison. Atropine, an 8-letter word, is an alkaloid found in the plant and is used to treat certain medical conditions. NIGHTSHADE, a 10-letter word, is another name for the belladonna plant and is also used in medicine. AMARYLLIS, a 9-letter word, is a genus of flowering plants related to the belladonna plant. All three terms are related to the belladonna plant and its uses in medicine and as a poison.