An MP3 player is a portable audio device people can use to listen to songs saved in the MP3 format. They can use USB cords or Wi-Fi to connect the device to computers, so that computer files can be transferred to players internal memory.
MP3s are audio files that have been made smaller by removing sounds that the human ear cannot hear. Many newer MP3 players can also be used to view images or movies, or play games, and can also play other formats, such as FLAC and MPEG-4 AAC. The most well-known MP3 player is the iPod. MP3 players can also be built-into a car or home stereo.
They were popular around the early 2000 but slowly lost popularity to the introduction to smartphones and apps like Spotify. Even with this loss in popularity, you can still get one today that can even connect to Spotify.