I am using a commercial sever with FreeBSD system without root account. I install gnuplot with my account. But, I can not set up fonts. So, I copy the fonts files in my home
Do not use /Symbol
. That will not use the Verdana font.
According to this page, the Verdana font includes greek letters.
Use UTF-8 encoding by adding set encoding utf8
to your gnuplot file. Then insert the unicode symbol (according to this page: θ, greek small letter theta, U+03B8) into the label string using your favorite text editor.