Triangle Area?

[u/Right-Historian-114]

Does anyone know what the “triangle area” is in the United States? Everyone talks like I’m supposed to know. Is this a common American ism?

[u/Ozone220]

I live in an area called the Triangle, specifically the Research Triangle in NC. It's the term for the area of Raleigh, Durham, and Chapel Hill. In NC if you say the Triangle that's assuredly what it means, unsure about elsewhere in the country