Latin phrase for Roman Army?

[mcbishop]

Not necessarily. In the first passage, the context indicates that Tacitus is referring to 'a' Roman army, not 'the' Roman Army; in the second, he is referring to the Roman army in that particular locality, as opposed to the enemy army.

Which I think was precisely my point. The Roman army don't refer to themselves in that way, but Tacitus does so, employing poetic licence (something not unknown in his writings) :-)

Mike Bishop