a very hearty, mixed vegetable soup, subject to enormous variation. From minestrare (to administer), probably because this was the only dish served at the meal. Note that it is redundant to say “minestrone soup”.
Minestrone (< Italian minestra 'soup' + -one (augmentative suffix)) is name for a variety of thick Italian soups made with vegetables, often with the addition of pasta or rice. Common ingredients include beans, onions, celery, carrots, stock, and tomatoes.