The PlayStation 2 sold over 155 million units, making it the best-selling video game console. Sony launched the PS2 in Japan in 2000, followed by North America and Europe, and its combination of affordable gaming, DVD playback, and backward compatibility helped it reach an enormous audience.
The console belonged to the sixth generation of video game systems and used Sony's custom “Emotion Engine” processor. Its built-in DVD player was especially important because the PS2 could serve as both a game machine and a relatively inexpensive home entertainment device. At launch, standalone DVD players were still costly in many markets.
The PS2 passed 100 million units shipped in November 2005 and exceeded 155 million sales by March 2012. Later figures put lifetime sales at roughly 160 million units. The figure in the question refers to the earlier official sales milestone; it does not change the answer. Common alternatives such as PlayStation 4 and PlayStation 5 sold far fewer units, while “PlayStation” alone refers to the original console rather than the PS2.