Miami /maɪˈæmi/ noun5 •A city, the county seat of Miami-Dade County, Florida.It may get even busier in town when a sleek train service called the Brightline debuts this summer, shuttling travelers between nearby West Palm Beach and Miami. — 2017 •Miami University. •A member of an indigenous North American people of Algonquian stock. •A number of townships in the United States, including five in Ohio, listed under Miami Township. •Ellipsis of Lake Miami, former name of Lake Okeechobee: a lake in Florida, the source of the Miami River. formsMiamis