Definition of "haystack" in English

noun

1. A mound, pile, or stack of stored hay.

2. (canoeing) A standing wave in a rapid.

3. (programming) The text string within which another string is searched for. (see: needle in a haystack)

4. (more generally) Any place or collection of items through which one searches for something that is rare and hard to find.

5. A dish composed of a starchy food (rice, tortillas, crackers, etc.) topped by a protein (beans, cheese, meat, etc.) in combination with fresh vegetables, assembled on the plate by the diner.