gnuplot5-x11 software package provides transitional package, you can install in your Ubuntu 17.04 (Zesty Zapus) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install gnuplot5-x11
gnuplot5-x11 is installed in your system.
Make ensure the gnuplot5-x11 package were installed using the commands given below,
$ sudo dpkg-query -l | grep gnuplot5-x11 *
You will get with gnuplot5-x11 package name, version, architecture and description in a table
| Distro | Ubuntu 17 04 zesty zapus |
| Section | Old Libraries |
| Package | gnuplot5-x11 |
| Version | 5.0.5+dfsg1-4ubuntu1 |
| Description | transitional package |
| Sub Section | oldlibs |