Definitions

Information systems
Information systems is the study of complementary networks of hardware and software that people and organizations use to collect, filter, process, create and distribute data. Any specific information aims to support operations, management and decision making.

World Wide Web
A World Wide Web is a system of interlinked hypertext documents accessed via the Internet.

With a web browser, one can view web pages that may contain text, images, videos, and other multimedia, and navigate between them via hyperlinks.
Using concepts from his earlier hypertext systems like ENQUIRE, British engineer,computer scientist and at that time employee of CERN, Sir Tim Berners-Lee, now Director of the World Wide Web Consortium (W3C), wrote a proposal in March 1989 for what would eventually become the World Wide Web.

The terms Internet and World Wide Web are often used in everyday speech without much distinction. However, the Internet and the World Wide Web are not the same. The Internet is a global system of interconnected computer networks. In contrast, the Web is one of the services that runs on the Internet. It is a collection of text documents and other resources, linked by hyperlinks and URLs, usually accessed by web browsers from web servers. In short, the Web can be thought of as an application "running" on the Internet.^[25]

Viewing a web page on the World Wide Web normally begins either by typing the URL of the page into a web browser or by following a hyperlink to that page or resource.

Communication protocol
A Communication protocol is a system of digital message formats and rules for exchanging those messages in or between computing systems and in telecommunications.

Software package
A specific piece of software which the system can install and uninstall.

Web service
A web service is a method of communication between two electronic devices over the World Wide Web. A web service is a software function provided at a network address over the web or the cloud, it is a service that is "always on" as in the concept of utility computing.

Software component
An individual software component is a software package, a web service, a web resource, or a module that encapsulates a set of related functions (or data).

Delegate: A person authorized to act on behalf of someone else. "Delegated" carries with it the connotation that one is acting as a representative of a superior in carrying out a task.
Proxy: A person chosen or elected to act for or represent another or others.
Reference/ Source: http://www.wikipedia.org/