C shell
From FreeBSDwiki
/bin/csh is where you'll find the binary of the C shell, so called because its syntax is very like the C programming language. It was written by Bill Joy of Sun Microsystems and is the only other shell besides the spartan Bourne shell (/bin/sh) that comes installed by default on a freshly-installed FreeBSD system.
Other shells that you can install and customize for ease of use are the bash, tcsh, psh, ksh, zsh.