What's the difference between a teaser trailer and a theatrical trailer?

The difference of a teaser trailer and a theatrical trailer is generally a teaser trailer is much shorter and of course the main purpose is to tease. These are often released online quite a while before the release, they do not give any of the plot away and only give glimpses of what is to come. Wherase with a theatrical trailer it is shown just before the movie release and also shows a fair bit of detail into plot, they are often longer as well.