What it actually means
Every device that connects to the internet needs an address so traffic knows where to go. That address is the IP. The version you have probably seen looks like 192.168.1.1, which is IPv4. The newer format, IPv6, looks longer because it was designed to handle billions more devices than IPv4 ever could.
There are two distinctions worth knowing. Public versus private, and static versus dynamic. Your router has one public IP that the rest of the internet uses to find your home or office. Inside the building, every laptop, phone, and smart bulb gets a private IP that only your own network sees. On top of that, most broadband providers hand out dynamic public IPs, which means the number you have today might be different in a fortnight. A static IP is one that never changes, and you usually have to ask for it. For most homes none of this matters in daily use. For some businesses it matters a lot.
At home
What this looks like in the house
Most households never see an IP address and never need to. You plug the router in, the devices find the internet, the football stream works, and life carries on. The only time it tends to come up is when a smart camera or a games console asks for a static IP to stop a connection issue, and even then your provider can usually sort it without you having to learn what any of the numbers mean.
In business
What this looks like at work
For a business, an IP address is sometimes the difference between staff being able to work from home and not. A static public IP lets you whitelist your office on a remote access VPN, host a server, lock down a CCTV system, or run a card terminal that the payment gateway expects to see at the same address every day. Without it, you spend Monday mornings re registering devices that suddenly cannot connect because the number changed overnight.