Public Key Infrastructure

Hey everyone! 
Can anyone please give me a simple definition of WHAT PKI is? Not only as what it does, but what it IS.
I mean from what I gathered here is that PKI is a group of protocols, policies, software and even people who are needed for creation and management of certificates right? And it involves Certificate Authority...
Any more clarifying definition will be appreciated!
Thanks in advance!

Can anyone please give me a simple definition of WHAT PKI is? Not only as what it does, but what it IS.
I mean from what I gathered here is that PKI is a group of protocols, policies, software and even people who are needed for creation and management of certificates right? And it involves Certificate Authority...

Any more clarifying definition will be appreciated!

Thanks in advance!

Comments
Does that help?
Yes, it does help me somewhat
Thank you!