HBO is an American television company. You usually pay extra to watch it. It is famous for making its own drama series — long, carefully made stories such as The Sopranos and Six Feet Under — and it also shows films. When people say “an HBO show”, they often mean that kind of serious, high-quality TV story, not a cheap daytime programme. The three letters first stood for Home Box Office: a box office is where you buy cinema tickets, and the early idea was films at home. Though actually, almost nobody unpacks the letters now; HBO is just a brand name. In Taiwan you will meet it as a paid cable or streaming channel. It is a name, not a normal English word you change like a verb.