Phishing
Phishing (password harvesting) is an illegal activity where someone attempts to acquire sensitive information such as user names, passwords and credit card information. Often, users are asked to enter these details onto a website which they are stolen from.
Pishing
The term Phishing originates from the internet argot leetspeak. Phishing often employs highly advanced imitation websites which steal digital information, however they often employ simpler messages like emails requesting bank information disguised as a desperate cry for financial help or a random donation from a wealthy individual.
The purpose of the fraudulent sender is to "phish" for, or entice people to share, their personal, financial, or password data. It's then used to commit crimes.