An ip name is a logical name for an IP address.
One or several IP name can be assigned to an IP address.
In other word, an IP name is a name under which the network adapter is known in the network.
1 network adapter = 1 IP address = one or more IP name
The IP name is mapped to the IP addresses using a name database.
The ip name is also known as domain name when the name is mapped to an IP.
The IP name is often mistakenly described as the host name, although the relationship of the host name and the IP name is not always unique. (ie A host can have several IP names, but it can only have one host name)
The IP name is known as the host in HTTP
A name database holds the relation from IP name to IP address
You can query the IP name with a reverse DNS if you know the IP.