XTERM running on Macbook-Air

Any particular reason you want xterm over Applications -> Utilities -> Terminal and an ssh connection? Or even iTerm2, another excellent terminal emulator?

As has been mentioned above, you need to install Xquartz to get an X11 display server, then logout, and login (or reboot) so that your macOS GUI session has the X11 named socked opened in /tmp and the DISPLAY environment variable defined for your terminal emulator sessions.

Xquartz works well, but the Mac mouse model that does not include a middle mouse button makes using X11 based apps difficult. You either have to remap the X11 app’s keys for copy & paste, or get a macOS utility that can simulate a middle mouse click. My preferred is BetterTouchTool, because it is a Swiss Army knife on all things macOS input (trackpad, mouse, keyboard, touchbar, clipboard manager, window snapping, etc…).

While I’ve used X11 based apps running on remote, Linux, Solaris, AIX (those are recent), and DIGITAL UNIX (renamed Tru64 UNIX), I’ve generally found it awkward, especially xterm (or pick another flavor Linux/UNIX based X11 terminal emulator) vs iTerm2 or macOS Terminal. The UI is part of it, in that it is not well integrated with the macOS UI, but also my Linux/Solaris/AIX platforms tend to be 2,000 miles away, and X11 is way too chatty for the accumulated 2,000 mile latency issues. gvim and gvimdiff were not too bad, but I still had to deal with echo back delays. Thankfully I can do 99% of my work via iTerm2, ssh (or Mosh) connections and tmux for session disconnect protection.

Have you got an actual PDP11 in your basement? 🤓

Those TEKTRONIX terminals were really cool back in the day.

I do remember TEKTRONIX 4014 monitors being used for CAD at Pratt & Whitney many years ago.

You need to install X11 for XTERM - https://www.xquartz.org

Couple XTERM alternatives to TEKTRONIX 4010 / 4014 Emulator source code projects. The first one is more likely to work on macOS and has some instruction to install prerequisites using Homebrew.

https://github.com/Isysxp/Tek40xx

https://github.com/rricharz/Tek4010

Disclaimer: I've not tried this... Your mileage may vary.

The X Window server is associated with the X display hardware, and is provided with XQuartz. The X Window clients can be local, or can be operating on one or more remote systems and accessing the display via remote X. Your configuration here is the X client and not the X server, so the X app is looking for a server to connect to. This is set by the DISPLAY environment variable or similar setting (VMS used DECW$DISPLAY), or by a parameter at app startup, or sometimes from a configuration file. X loves configuration files. X. Really. Loves. Config. Files.

XQuartz includes Xterm, though the version installed might differ.

Tek 4014, 4125, and other such largely post-dated PDP-11 (those were running out of address bits by the early 1980s), and the Tek terminals were probably more commonly seen on VAX/VMS, Sun, Apollo, and other gear from the 1980s.

If you’re into this stuff, the vt100 may be of interest: https://vt100.net/

And a maybe: https://www.macterm.net/features/

I am fairly certain that the macOS Terminal and iTerm2 do not support TEKTRONICS 4010 4014 terminal emulation. It's not VT100, etc. They are vector graphics terminals more akin to an oscilloscope. Used primarily for CAD and other early imaging needs.

The VT100 website has Tek docs, to be clear. The VT100 itself is ANSI with extensions, and not at all like the Tek 4014. Which pre-dated ANSI. The Tek 4014 had great graphics, but was otherwise a hassle to work with in a mixed environment as it spewed on ANSI sequences. The vector displays on the Tek 4014 and on IMLAC PDS-4 and other vector-based systems did usually have marvelous Asteroids games, though. In mixed-terminal environments, the Tek 4125 was just easier to integrate and work with. But as for the OP, finding something that understands the Tek sequences is going to be the central part of the project, whether that’s xterm or otherwise. And if it’s xterm, it’s also getting X working.

xterm details: https://invisible-island.net/xterm/