What Does It Mean?

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From our dictionary:
ul•ti•ma Thu•le

(ul'tu•mu thOO'lE; Lat. ool'ti•mä" tOO'le),
1. (italics) Latin.the highest degree attainable.
2. the farthest point; the limit of any journey.
3. the point believed by the ancients to be farthest north. Also called Thule.