Sentence:  1 2 cup minced celery 1 4 cup minced onion 1 2 cup tomato ketchup 1 2 cup water 1 4 cup vinegar 2 tablespoons brown sugar 1 tablespoon Worcestershire sauce 1 tablespoon prepared mustard 1 2 teaspoon salt 8 frankfurters <WSD>Combine</WSD> first 9 ingredients in skillet . 
Meaning of the word marked with <WSD> tags:  combine so as to form a whole; mix