no. citrix is not a vpn, it is a terminal emulator of sorts. you may use a VPN to connect to your Citrix Host, but the Client -> Host thing is basically dummy terminal stuff. Like the old days of mainframes and dumb terminals, only now it is emulated on your real computer. It may use a Virtual Private Network to get from your home PC to the office mainframe in a secure fashion. Such as if you have a cable modem and your office wants to make sure other people cannot spy on your citrix traffic back to the office, you may connect through a VPN tunnel, which is just a VPN connection through the internet back to your office.
Citrix allows you to work away from the Citrix Server as if you were actually using the server. A VPN allows you to work away from the LAN as if you were actually on the LAN.
EV