Disjoint sets, also known as disjoint-set data structures, are collections of non-overlapping sets. Each set contains unique elements, and no element belongs to more than one set. This structure is useful for grouping items and efficiently managing relationships between them, such as in network connectivity or clustering problems. The primary operations associated with disjoint sets are union and find. The union operation merges two sets into one, while the find operation determines which set a particular element belongs to. These operations help maintain the integrity of the sets and enable quick queries about their relationships.