ISP is a company and organization that provides users with Internet access and/or Internet information services. The former is also called IAP (Internet Access Provider) and the latter is also called ICP (Internet Content Provider). The definition we see now is usually that ISP is an Internet access service provider, but it is not accurate.
NSP (network server provider)
The definition is basically the same as ISP, and the scope is not limited to the Internet, but includes all computer networks.