can some one please explain
zombie
orphan
defunct
and how they r related
before someone thinks this is a home work it not 
let me tell what my idea was till date
zombie process or defunct process is a process that has completed execution but still has an entry in the process table
then y 2 different names
orphan is one who's parent process is killed
but now i feel like a 
form search i got
When a process ends, all of the memory and resources associated with it are deallocated so they can be used by other processes. However, the process's entry in the process table remains.(at this point is the node orphan ???? )
The parent can read the child's exit status by executing the wait system call, at which stage the zombie is removed.
now y is orphan not same as zombie
pls let me know
thnx
i got a beautiful article for zombie and orphan
WikiAnswers - What is Zombie Process and Orphan Process
that leaves me with one question
zombie and defunct are one and the same???
Not exactly, the ps command checks to see if a process is in the zombie state. If so, it will display <defunct> as the name and as the command line of the process. But the author of ps could have picked "nonesuch" or "tilt" or "not at home" just as easily. The kernel knows what a zombie is, but it never heard of "<defunct>".