I see a lot of the word 'expressiveness' when people want to stress one language is better than the other. But I don't see exactly what they mean by it.

• Is it the verboseness/succinctness? I mean, if one language can write down something shorter than the other, does that mean expressiveness? Please refer to my other question - http://stackoverflow.com/questions/2411772/article-about-code-density-as-a-measure-of-programming-language-power
• Is it the power of the language? Paul Graham says that one language is more powerful than the other language in a sense that one language can do that the other language can't do (for example, LISP can do something with macro that the other language can't do).
• Is it just something that makes life easier? Regular expression can be one of the examples.
• Is it a different way of solving the same problem: something like SQL to solve the search problem?

What do you think about the expressiveness of a programming language? Can you show the expressiveness using some code?

What's the relationship with the expressiveness and DSL? Do people come up with DSL to get the expressiveness?