* Current usage - how much of it is deployed.
* Growth - how much it's being used for new projects, worked on, written about, etc...
For instance, Cobol is still fairly widely deployed in some environments, but growth is probably negative, as it's being replaced by Java. Java is very widely used, and is still probably growing, although probably not as much as things like Ruby, which have grown a lot; which is easy when you start from a small base.
If dead = in stasis, then computer languages are like popular comic book characters. They may die, but someone will eventually bring them back.
<pedantism>
Edit: Thought about this more, and some people almost certainly say "like" more than any other word. (Un)surprisingly, your sentence loses little meaning if the actuallies are replaced with likes, commas optional.
</pedantism>Edit: also, there are many new Delphi/Pascal projects, just check out http://www.lazarus.freepascal.org/ the "True Death" is highly exaggerated.
It certainly does not mean "dead" as in "not being used". Such a term -- let's call it "the True Death" -- would be nigh-useless in a discussion of computer languages, because very few successful languages reach that state. The code doesn't rot. COBOL lives. FORTRAN most definitely lives. Lisp is older than everything and it is very much alive. Pascal might be an exception: You really never hear of anyone writing new Pascal code. Perhaps it is approaching the True Death. Or perhaps some of the more obscure assembly languages of decades past are Truly Dead. But I wouldn't be surprised if they weren't. There are people writing Atari 2600 assembly language right now. Maybe even more than there were in 1982.
The discussion is complicated by the evolution of languages and the desire to rehabilitate old trademarks. Applesoft BASIC is far closer to the True Death than "Basic" is, because Microsoft stole the name and applied it to a rather different creature. "Lisp" cannot die, but you could point to one of the thousand dead dialects of Lisp and call that dialect a "Truly Dead language". Eventually you get trapped in a pointless semantic debate, like the one you flirt with here: If the JVM is alive but Java is dead, is Java alive?
At any rate, now that we've established what we mean: Yeah, Java is arguably "dead". It has reached an equilibrium where anything you might do to change the design creates more problems than it solves: It breaks back compatibility, or it creates an impenetrably complex monster that only a relatively small number of people can understand. It's also very easy to argue that Microsoft Windows "died" around the release of Windows XP: Since then, the company has devoted uncounted thousands of programmer-hours to create an OS that much of the market has concluded is no improvement over XP. That's what static equilibrium looks like.
But this doesn't mean that we won't have Java and Windows to complain about for years and years, if not decades and decades. In software the dead do not truly die. They just stalk the earth as vampires. (I originally wanted to say "zombies", but that's wrong. Zombies are slow and stupid. Undead languages, on the other hand, are often amazingly competent and smart despite being technically dead. They've got a lot of experience.)