Tasty salad concoction. The base ingredient is cabbage; other ingredients often include mayonnaise, vinegar (usually cider vinegar, red and green bell peppers, celery seeds, sugar, salt, pepper, and carrots.

The Dutch origin of the name came clear to me one day when I was reading through Mijn Eerste Woorden Boek and found that kool (pronounced "cole") meant cabbage. I was highly and inexplicably amused.