Java SE (full name: Java Platform, Standard Edition, old names too many to enumerate) is a specification of a programming platform that consists of:
- The Java programming language itself.
- A virtual machine that the Java compiler targets.
- A set of standard libraries.
- A set of standard utilities related to the above.
Confusingly it's also the default name of a specific implementation of the Java SE specification (the proper name being various combinations of the Java SE name with "JDK" or "JRE" attached). You can find out more about Java SE (and most especially the Oracle JDK/JRE implementation) on Oracle's page for it (latest stable version).
Java EE (full name: Java Platform, Enterprise Edition, old names, as above, too many to enumerate) is a specification of another programming platform—a framework, really—that is built up on top of the Java SE platform. This platform is intended to add functionality for modern business applications like web applications, n-tier architectures, etc. There are a myriad of implementations of this specification out there—both open source and proprietary—including Oracle's Glassfish/Java EE SDK, IBM's Websphere, Apache's Geronimo, etc. You can find more information about Java EE (and the Glassfish/Java EE SDK implementation of it) again on Oracle's page.
