Multisets

Part of speech: noun

Definitions

1. A collection of elements where repetitions are allowed
2. A set in which the same element can occur multiple times, differing from a standard set by counting duplicates
3. An unordered arrangement of items that can include the same item multiple times, utilized in various mathematical contexts

Etymology: "Multisets" is the plural of "multiset," a term coined by the Dutch mathematician Nicolaas Govert de Bruijn. The word is a simple compound: the prefix "multi-," from Latin "multus" meaning "many" or "much," joined to "set," so that a multiset is a set in which an element may appear more than once. The plural form simply follows the ordinary English pattern for nouns ending in a consonant sound, so "multisets" is the plural of the singular "multiset" with the regular "-s" added.