HDMI-Transfer via Air?

An HDMI lead?

What is that please? I understand the words but not the meaning (no native englisch speaker).

FW

A cable. Wireless HDMI is quite involved, unreliable and expensive, I think. You need a transmitter and a receiver! One solution is to put the Pi you'e working on near the TV and just plug it in, then use remote desktop (VNC, which you can enable on the Pi via the configuration menu) from another computer to work remotely. The second computer on which you work can even be a Pi Zero.

This still seems quite involved and sub optimal, so it's probably not what you want or what you meant.

I assume Chris didn't read the subject line and proposed you use an HDMI cable while you presumably want a wireless solution.

Possibly you could put a media server like minidlna on the Pi and have the TV play from there? Assuming a TV with networking and DLNA support. A Chromecast might work too.

With a quick Google, looks like wireless HDMI boxes exist too. Drahtlose HDMI suchen und so weiter.