IP address
An Internet Protocol address (IP address) is a numeric label to identify devices on the internet. This unique identifier consists of four numbers separated by dots, e.g. 192.0.2.1.
Each of these four numbers can be any number in the range of 0-255. Though, some IP addresses are reserved for special purposes. So, there are a bit less than 4.3 billion (ca. 2^32) unique IPv4 addresses available (32-bits). These available addresses are slowly used up which nobody anticipated when it was designed in the past. Therefore, a new standard IPv6 with 128-bits was introduced which makes a huge quantity of addresses available (2^128 = a number with 39 digits). Here are two examples of IPv6 addresses:
2001:db8:3333:4444:5555:6666:7777:8888 and2001:db8:3333:4444:CCCC:DDDD:EEEE:FFFF
There a few more things I don't want to explain in detail. A global IP address is an address that is publicly accessible to everyone on the internet. A local IP address is an address that is only visible within your (wireless) local area network (LAN or WLAN). Also, there is Network address translation which translates and keeps track of the mapping between global and local addresses; basically a gatekeeper/switchboard between the public internet and your private local network.