Gnome terminal is known for being a resource hog. When it reached 130 megabytes for a recently-opened terminal I looked into it.
Thanks to Gnome Live memory reduction this was fairly easy.
Using cat /proc/nnn/smaps I could see Korean and Japanese fonts using lots of memory. I don't usually need these...Try searching for "batang", "kochi" and "uming"- I've removed these from my Ubuntu.