Chromecast

Chromecast is a digital media player from Google. It plugs into the HDMI port on a TV. The Chromecast shows content from a smart phone, tablet or PC on the tv. 
The Chromecast has an HDMI plug, and a micro-USB port. Power comes from a USB port on a TV or from the included power adapter.
Chromecast needs both Wi-Fi and a phone, computer, tablet, etc. to work. Many apps support Chromecast, such as Spotify, Youtube, Viaplay, Netflix, Dplay, Disney+, HBO, and Hulu. 
There is also a newer Chromecast with Google TV a USB-C port instead of micro-USB. It has up to 4K resolution.