Credit terms are very foreign to me. Please help!

What do these terms mean?
1. Charge off
2. Account closed... is that good?
3. Transferred/Closed
4. Purchased by another lender

Am I correct when I say that if the account was purchased by another lender, then possibly that account and/or delinquency may be on your credit for more than 7 yrs?

Thanks in advance to all you smart people!

Layman terms...
Charge off... you didn't pay, they figured they would never get their money from you, so they wrote it off
Account closed... means you can't charge on it, it won't add more interest, but may/may not still owe a bill
Transferred/Closed... you got another credit card with lower rate and transferred that card to it (paid it off with another account)
Purchased by another lender... some companies sell their accounts off, meaning who you pay changes, but nothing else would change... this shouldn't change the seven year rule (it didn't on one of mine)