CIDR
acronymnetworking
Stands for: Classless Inter-Domain Routing
A compact way to write an IP network as an address plus a prefix length, like 10.0.0.0/8.
Classless Inter-Domain Routing (RFC 4632) replaced the old rigid A/B/C classes with a slash number saying how many leading bits are the network. It is the notation behind almost every subnet decision, and the input our CIDR tools compute against.
Also known as: cidr, slash notation, prefix length