Where can I buy Perspex sheets?
Perspex is a brand name, but I've most often heard the name used by British English speakers. A similar product is Plexiglas which is also a brand name. In the US, people use the word "Plexiglas" generically and I believe that's true of the word "Perspex" in Great Britain. If you go into Home Depot in the US and ask for Perspex you're likely to get a quizzical look. If you ask for Plexiglas, you may not get that brand, but they'll know what you're talking about.