asterisk users - Dec 2004 - What is the difference between monitoring and recording???

Can anybody explain me the difference between monitoring and recording?

Can I record a conversation during a phone call, e.g., I find that I 
should note that, and press "7" to record till I press again
"7" (or
whatever key is good for that.) while the rest of the phone call will be 
not recorded!

bye

Ronald