U+228E "⊎" Multiset Union Unicode Character

U+228E "⊎" Multiset Union is a mathematical symbol used to represent the union operation specifically for multisets, also known as bags, where each element's multiplicity is summed rather than simply combined without duplicates as in standard set union. For example, if a multiset contains two copies of 'a' and another contains three, their multiset union will contain five copies of 'a'. This operator is essential in fields like combinatorics, database theory, and formal language processing where the frequency of elements matters. Its design features a plus sign nested inside a union symbol, visually indicating the additive nature of the operation.