“Phishing” is when the sender of an email tries to trick recipients into providing passwords or sensitive information. That information can then be used to commit identity theft, or enter password-protected sites using your account. Phishing emails claim to be from legitimate sources and use avenues such as an authentic-looking email, and/or a fraudulent web page that asks you to supply personal information (name, address, financial information, passwords, etc.).
As phishing schemes become more sophisticated, it becomes increasingly important to be vigilant, even if the message appears to come from a family member or somebody you know well. Always be suspicious of requests for personal information that come via email, particularly requests for passwords, banking information, or wire transfers of money.