(I) The style of identifier that is defined for subtrees in the
Internet DNS -- i.e., a sequence of case-insensitive ASCII labels
separated by dots (e.g., "bbn.com") -- and also is used in other
types of Internet identifiers, such as host names (e.g.,
"rosslyn.bbn.com"), mailbox names (e.g., "rshirey@bbn.com") and
URLs (e.g., "http://www.rosslyn.bbn.com/foo"). (See: domain.
Compare: DN.)
Tutorial: The name space of the DNS is a tree structure in which
each node and leaf holds records describing a resource. Each node
has a label. The domain name of a node is the list of labels on
the path from the node to the root of the tree. The labels in a
domain name are printed or read left to right, from the most
specific (lowest, farthest from the root) to the least specific
(highest, closest to the root), but the root’s label is the null
string. (See: country code.)