What is actually meant by the term "web-based development/solutions/applications"? In particular in relation to java? I hear this terminology all the time but I don't really understand what it means... :$

An application designed to be used over the internet (usually through the use of a browser), written in Java.

mostly it's marketing hype.
A project title or description containing the word "web" or "web based" will get far more budget when presented to venture capitalists and company boards. A resulting product will likely also sell for more money (despite being usually less userfriendly, slower, and have less functionality than the equivalent desktop system).