Is the Entente expressly mentioned to be a "dreadnought"?
Yes. It is a call made from
the "Dreadnought Entente" to
Epsilon IX. Twice in fact, since the same call is made twice, once by a male and then immediately after by a female voice.
I have the main call to the Columbia (mostly) and some other things printed out somewhere. I'll see if I can find it.