Terms A domain name (or just “domain”) is a string the form bar.foo.com.. Not all domains refer to physical machines; for example, one of my domains, k.maelvls.dev., do not point to any physical machine. We often represent the domain name space using a tree. Each node is a domain. Leaves and nodes may have A records. Here is a simple example of the domain space represented as a tree: . ├── com.
