Packet
On the Internet data is broken up into small chunks called packets.

Password
A code used to gain access to a system.

Peripheral
An external hardware component (printer, disk, etc.) that is externally connected to a computer and serves it. 

Ping
Software that allows a user to check if a connection exists between his/her computer and another computer.

Plug-in
An application written in order to broaden the Web browser's features.  After you download the plug-in to your computer and place it in the plug-in folder, your Web browser will be able to offer you additional features. For example, after you install the Emblaze plug-in, you'll be able to play Emblaze movies, found on the Web.
(See Emblaze, application).

POP-Post Office Protocol
Protocol for storing and retrieving E-Mail messages.(See protocol, E-Mail.)

POP account
A user's E-Mail account on the Internet.  
(See ISP, mailbox.)

Postmaster
The person who operates the host and is in charge of the E-Mail function. (See host, 
E-Mail.)

PPP-Point to Point Protocol
Protocol which enables communication on the Internet using a modem and a telephone line. (See modem,  protocol.)

Protocol
A language for communication between computers.  Protocol consists of a series of rules and commands meant to allow for satisfactory communication between computers.  The protocol that allows for communication on the Internet is TCP/IP.
(See TCP/IP.)

Public domain
See freeware.