convivium
n.— «Miami and Tallahassee have chapters, which the Slow Food folk refer to as conviviums. I guess it is slower and more impressive to say than “chapter.” And the plural “convivia” clearly has more cachet than “chapters.”» —“Central Florida sets a great table: Pull up a chair and dig in” by Heather McPherson Orlando Sentinel (Florida) Dec. 27, 2006. (source: Double-Tongued Dictionary)
Further reading
Need a slang term that can replace just about any noun? Try chumpie. If you’re from Philadelphia, you may already know this handy placeholder word. And there’s Queens, Brooklyn, Staten Island, Manhattan, and … The Bronx — why do we add...
The owner of a Berlin, Maryland, produce stand wants to know: When a customer is buying four ears of corn, should they say I have four corn or I have four ears of corn? Corn is a mass noun that can also be counted as a plural, just as we might say I...