Cocktail party staple that may contain the ends of 17-, 25-, 38-, 42- and 55-Across

CHEESEBOARD

Think of a shared platter often found at gatherings, featuring a variety of sliced dairy products.

This clue hints at a common item found at cocktail parties, specifically a "cheeseboard." The wordplay involves taking the last letters from the answers to 17-, 25-, 38-, 42-, and 55-Across and combining them to form "cheese." For example, if those answers ended with C, H, E, E, and S, you'd get "cheese," which fits into "cheeseboard." It’s a clever way to piece together the answer using parts of other clues.