“Alpha” and “Beta” are titles the Software industry uses for software that isn’t quiiiiiiiite finished yet. Generally, these products aren’t generally available, are likely to change quickly, might not be well documented and might misfire in spectacular and sometimes unpleasant ways. Both of these terms describe software that is expected to have bugs, but they refer to different levels of bugginess.
An Alpha usually refers to software that’s very early on it its development cycle. It’s often just barely ready for use, with highly limited features, plenty of bugs and stability issues.
A Beta is a product that’s mostly ready for use. It might still be lacking some features and have a few bugs, but it’s generally able to do what it’s supposed too, most of the time.