What is a private IP address ?

Its companies internal ip address , which is been hidden due to security reason from outside network .

A private IP address is a non-Internet facing IP address on an internal network. Private IP addresses are provided by network devices, such as routers, using network address translation (NAT).

AINA has divided up addresses into two parts : 

1.Private ip address

2.Public ip addresses 

Private ip address : used in private network like LAN/WAN for our private communication.Private ip address can not be used on internet.

Ranges :

.0.0.0 -...

..0.0 -...

..0.0 -...

Note: Private ip addresses are reusable because we can use same up addressing in two different LANs.

Example. Reliance and TATA  both can have same ip addresses like.0.0.0 -... in their office andit will not cause any problem .

Private IP Addresses are logical addresses which are not facing internet. These are used in internal networks. 

RFC mentions which are the ranges should be used for private addressing. Ranges are

..0.0-...

..0.0-...

.0.0.0-...

Its a unique ID assigned to every system to access by network

ITS UNIQUE ID FOR EVERY SYSTEM TO ACCESS NETWORK

Private IP adresses are no routable IP adresses on Internet.  There is3 ranges :

.0.0.0/8 ..0.0/..0.0/