Beta

A beta as a stage is a stage of development that indicates that the software has all of its planned features implemented, but is unstable and not yet ready for a final release.

The term beta software refers to software which is currently in the Beta stage of development (i.e. has all the main features but is not ready for release).

Name
The word "beta" comes from the Greek letter with the same name, which is the second letter in the Greek alphabet (corresponds to the English "B"). Others refer to this stage as the preview stage, technical preview, or early access.

Uses of Beta Software
The main use of beta software is demonstration of the product. A beta version is sometimes also released to a limited amount of people, or even to the public for testing.

Demonstration
Beta software is often used so that the developers or publishers could demonstrate the product to the public or its consumers. Major companies like Microsoft always showcase their upcoming products, and the most recent example has been Windows Vista.

Testing
In beta software, the main features have already been implemented, and the software is usually near its final form. So it would be very wise to either release the product to a limited audience or even to the public for testing. Features would be tested to see whether or not they work properly, and people would search for bugs.