Why is the stadium commonly referred to as San Siro? That’s simply because it was built in the San Siro district in Milan, a major city in the north of Italy.

The district is located about 5 kilometres to the northwest of the city centre. Apart from housing several other sports complexes, the district is famous for housing the city's most important horse-racing track.
Even though the stadium is commonly known as “San Siro,” the stadium is officially known as the “Stadio Giuseppe Meazza.”

When it was constructed, the original name of the stadium was the “Nuovo Stadio Calcistico San Siro” (San Siro New Football Stadium). That’s a mouthful, so this was shortened to simply the “San Siro.”It wasn’t until March 2, 1980, that the stadium was renamed after one of the most famous footballers in Milan history, Giuseppe Meazza, who had died a year earlier. He played for both clubs (only briefly for AC Milan) and was the manager of Inter two times as well.
For a period of time, Inter fans referred to the stadium as simply the “Meazza” because the man had much closer ties to Inter Milan than AC Milan.

It is the 4th biggest stadium in Europe if we don’t include national stadiums such as Wembley or the Stade de France. Only the Camp Nou of FC Barcelona, Signal Iduna Park of Borussia Dortmund, and the Santiago Bernabéu of Real Madrid have a higher capacity than the San Siro Stadium.