P
Packet
Data sent across a network, divided into small, easily transmissible chunks.
Packet Switching
Method to send data across a network. Data is broken up into packets (chunks). Each packet has the address of the sender and the address of the destination. This way, packets from many different sources can be sent on the same line at the same time. See TCP
Phrase searching
The search feature supported by most search engines that allows you to search for words that usually appear next to each other. It is possibly the most important search feature.
Plug-in
An application, software, that’s used along with a Web browser to view or display certain types of files as part of a Web page. Shockwave from MacroMedia is a plug-in that allows the browser to display interactive multimedia.
Parse
To analyze or separate (input, for example) into more easily processed components.
PDF-Portable Document Format by Adobe
The standard for the secure and reliable distribution and exchange of electronic documents and forms around the world. PDF is a file format that preserves the fonts, images, graphics, and layout of any source document, regardless of the application and platform used to create it. (from www.adobe.com)
PEBCAK
Problem exists between chair and keyboard. Unfortunately when someone complains of a glitch in a program or some software, often the problem is a PEBCAK.
Perl - Practical Extraction and Report Language
Perl is a powerful computer language, especially used for writing CGI scripts which handle input/output actions on Web pages such as forms, questionnaires, bulletin boards, etc.
Pixel
The cell is nature's building block, and the pixel is the Web designer's. Pixel is one of those half-baked half-acronyms: PICture ELement. It refers to how monitors divide the display screen into thousands or millions of individual dots. A pixel is one of those dots.
Platform
Software developers need to know which platform their software will be running on. A platform can be an Intel processor running Windows, a Macintosh running OSX, or any combination of hardware and software that works together. Platforms are important for Web designers to understand, because they need to make sure their pages will work on more than one platform. Different browsers display Web pages differently on various platforms. Since the Internet itself is a cross-platform system, designers need to test Web pages on different combinations of machines and browsers to ensure the widest possible audience will be able to view their sites.
POP-Point of Presence
POP is a service provider's location for connecting to users. Generally, POPs refer to the location where people can dial into the provider's host computer. Most providers have several POPs to allow low-cost access via telephone lines.
POP-Post Office Protocol
A set of rules which allows you to send and receive e-mail.
Portal
A Web site that attracts visitors by offering free information, or free services on a daily basis. When you are on a portal site, you can use this site as a basis to explore the Web. The most famous portals are these major search engines: AltaVista, Excite, HotBot, Lycos, InfoSeek and Yahoo.
POTS
This is an acronym for Plain Old Telephone Service. Important to know, don't you think? Analogous with Snail Mail, which refers to the services of the United States Postal Department.
PPP-Point-to-Point Protocol
PPP is an Internet connection where phone lines and a modem can be used to connect a computer to the Internet.
Protocol
A set of standards that define how traffic and communications are handled by a computer or network routers. Think "rules."
Proxy
Form of security on the Internet. When you use a proxy or proxy server, you send a request to a server on the Internet via this proxy. For the server on the Internet it looks like the request is coming from the proxy, not from your machine.
Push media
New method to collect information on the Internet. You can subscribe to a push agency to deliver you all the information you need about a particular subject, so you won't have to scour the news by yourself. Many newspapers, for a fee, will offer this service.

Q
Query
Request for specific information from a database.
Query string
Your input in requesting information to a server on the Internet. For example, when you perform a search on Yahoo!, you'll see a question mark in the URL, followed by some strange text-string. Everything after that question mark belongs to the query string. A query string is data input for the CGI script on that particular Internet server.
QuickTime
This is a digital video standard developed for Apple Macintosh computers. Special viewing applications are needed to run QuickTime movies.

R
Redirect
By using particular HTML-code in a Web page, one can redirect the visitor seamlessly to another Web page.
Relevance
A measure of how closely a database entry matches a search request. Most search engines on the Web return results based on relevance. The specific algorithm for computing relevance varies from one service to another, but it's often based on the number of times terms in the search expression appear in the document and whether they appear in the appropriate fields.
Relevancy Ranking
A ranking of results, items retrieved form a database, based on the relevance score assigned by a search engine.
Response time
Time between sending a request to a server, and the complete delivery of the requested data, i.e. a web page fully downloaded.
Rollover
Rollover is a widely used dHTML (dynamic HTML) effect. Its name originally coming from Macromedia Director's scripting language, Lingo. Buttons are the most common use of rollovers. The user "mouses-over" the button to see a change in the button's look, a click on the button could result in yet another look.
Root
1. Top-level directory from which all other (sub)directories branch out.
2. On a UNIX system, the system administrator's account (also known as the superuser account). For security reasons, only the system administrator is allowed to log in as root.
Router
A communications device designed to transmit signals via the most efficient route possible.