The annoying bit is that jail has a specific meaning on FreeBSD that that is a kind of virtualization, somewhat similar to LXC. It looks like 90% of the chroot-jail questions are tagged Linux because many people have confused the term.
I think that we need to go through jails, jail, and chroot-jail tags. All three should be completely removed and in the cases where appropriate we add a tag like freebsd-jail. For the questions not actually about a freebsd jail we retag as chroot.
I am not sure a synonym is appropriate. I hope if we eliminate the tag it won't come back?
There are also a smattering of questions that don't seem to be about a chroot setup, or freebsd-jails, and instead asking about some general application virtualization type setup. We probably can't just do a mass-retag. People will need to look at the questions individual and re-tag as needed.