Answer by hirsch for How to change default terminal application in Gnome-Shell

On Ubuntu / LinuxMint to set the terminal emulator app for Nemo's

• file explorer right-click
• Ctrl+Alt+T Shortcut

executing the following allowed me to set terminator as default

gsettings set org.cinnamon.desktop.default-applications.terminal exec terminator

Depending on your distro's Desktop/xserver setup and which file explorer you use, you might have to replace org.cinnamon.desktop with org.gnome.desktop or maybe even org.kde.desktop.

Suggestions can be found by calling gsettings:

gsettings  list-schemas | egrep -i "desktop"

For LinuxMint19&Nemo, the cinnamon-variant worked straight away, without even logging out.

(came from https://unix.stackexchange.com/questions/336368/how-to-configure-nemos-right-click-open-in-terminal-to-launch-gnome-terminal)