[stack] So what is a concatenative language?

I've made an attempt at creating a more formal definition of
concatenative languages which I posted on my blog (
http://cdiggins.com/2007/04/27/what-is-a-concatenative-language/)

"A concatenative language is a context-free language that can be
expressed using a concatenative grammar. The defining characteristic
of phrases in a concatenative language, is that if A and B are valid
phrases in a concatenative language L then the concatenation of A and
B is also a valid phrase in L."

"A concatenative grammar is any context free grammar G, where S = S S
is a valid production rule."

"Flat concatenative languages are simply the set of all strings over a
given alphabet".

Any thoughts or comments?

Cheers,
Christopher Diggins