Packet flags - What is: URG, ACK, PSH, RST, SYN, FIN

Hi,
What is this flags(In packet): URG, ACK, PSH, RST, SYN, FIN?
Very thanks. :)

My memory let me down on some of these so I googled this for you :)

# CWR ECE URG ACK PSH RST SYN FIN
# CWR - Congestion Window Reduced
# ECE - Explicit Congestion Notification echo
# URG - Urgent
# ACK - Acknowledgement
# PSH - Push
# RST - Reset
# SYN - Synchronize
# FIN - Finished

ref: http://search.cpan.org/src/PAULV/POE...02/IPTables.pm

Very thanks The_Duck :).