What it is:
A layoff is a temporary or permanent termination of employment by an employer.
How it works/Example:
Let's say John Doe works for Company XYZ. He has worked there for 15 years. Company XYZ begins having cash flow problems and has to reduce its labor expense in order to avoid going out of business. In turn, it decides to shed 1,000 workers, of which John is one. This mass termination is called a layoff.
A layoff is not the same as being fired. Firings typically occur when an employee is at fault or has disobeyed company policies; terminations are not necessarily a direct reflection of a particular employee's performance (although it takes a village to wreck a company).
Why it matters:
However, people often get some indication that a layoff is coming. The federal Worker Adjustment and Retraining Notification (WARN) Act requires employers to provide 60 days' notice (sometimes more) of plant closings and mass layoffs. However, this applies to companies with more than 100 employees (and that 100 generally cannot include people who have been with the company for fewer than six months or part-timers).