IPv4
/ˌaɪ piː viː ˈfɔːr/ · Abbreviation · Development
Definitions
The fourth version of the Internet Protocol, which uses 32-bit addresses written in dotted-decimal form such as 192.0.2.1. Its limited address space led to widespread use of NAT and eventually to the adoption of IPv6.
In plain English: It is the older internet addressing system that identifies devices using numbers like 192.168.1.10.
Example: "The pod can reach the old printer only over IPv4 because that subnet never got dual-stacked."