States headers --need help please.
 

Hello,
Can I get some help?
using ps command I see headers, TTY is the reminder header for me to understand all headers.
Q: What is the meaning when TTY the following cases, because I don't understand:

And What is the use or importance of the Pseudo terminal Slave device (pts)?
Please, need help.
I looked and man ps and man tty it helped me alot but still this two points can't understand them.

Does this help?
http://en.wikipedia.org/wiki/Pseudo_terminal

Thank you, but I still face hard to get what I need from that page or any search source.
I need answer with explanation.
If anyone have any clue please provide me.