ultima Thule 极北地区, 遥远不为人所知的地区
ultima thule[ noun ]
the geographical region believed by ancient geographers to be the northernmost land in the inhabited world
<noun.location>
Ultima \Ul"ti*ma\, a. [L., fem. ultimus last.]
Most remote; furthest; final; last.
{Ultima ratio} [L.], the last reason or argument; the last
resort.
{Ultima Thule}. [L.] See {Thule}.