a very tall column (=upright stone post) with a statue of Admiral Nelson on the top of it in Trafalgar Square in central London. It was built to honour Nelson, who was killed at the Battle of Trafalgar, where the British navy defeated the navy of Napoleon in 1805. It is one of the best-known sights in London.
Definition from the Longman Dictionary of Contemporary English Advanced Learner's Dictionary.
Dictionary pictures of the day
Do you know what each of these is called?
Click on any of the pictures above to find out what it is called.