Simplify the following text for a Grade 16 native English-speaking person.
Original: Some of the greatest orchestras today include : the New York Philharmonic Orchestra , the Boston Symphony Orchestra , the Cleveland Orchestra , the Los Angeles Philharmonic Orchestra , the London Symphony Orchestra , the London Philharmonic Orchestra , the BBC Symphony Orchestra , the Royal Concertgebouw Orchestra , the Balmacewen School Orchestra , the Vienna Philharmonic Orchestra , the Berlin Philharmonic Orchestra , the Leipzig Gewandhaus Orchestra , the St Petersburg Philharmonic Orchestra , the Israel Philharmonic Orchestra , and the NHK Symphony Orchestra ( Tokyo ) .
Simplified: A smaller-sized orchestra for this time period ( of about fifty players or fewer ) is called a chamber orchestra . A full-size orchestra ( about 100 players ) may sometimes be called a `` symphony orchestra '' or `` philharmonic orchestra '' ; these modifiers do not necessarily indicate any strict difference in either the instrumental constitution or role of the orchestra , but can be useful to distinguish different ensembles based in the same city ( for instance , the London Symphony Orchestra and the London Philharmonic Orchestra ) .