Meaning

noun perennial Eurasian herb with reddish bell-shaped flowers and shining black berries; extensively grown in United States; roots and leaves yield atropine

noun an alkaloidal extract or tincture of the poisonous belladonna plant that is used medicinally

originBorrowed from Italian belladonna (altered by folk etymology: bella donna (“beautiful lady”)) from Medieval Latin blādōna (“nightshade”), of Gaulish origin. The folk etymology was motivated by the cosmetic use of nightshade for dilating the eyes.

Etymology from Wiktionary, CC BY-SA 3.0