I believe that generally on *nix platforms, it's usually "/home/<username>". so if my username was "fred", my home directory would be "/home/fred". I can also use the tilde character '~' as a reference to my home dir. so wherever I am, "cd ~" would take me to my home.
I also think you can use the tilde so see someone else's directory, if you know their username. so you could do "cd ~fred" to see fred's home dir, or an "ls -al" to see the permissions on it.
There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors