The most common and most likely answer to this crossword clue is the 3 plus 5 letter word OLD WORLD
I've seen this crossword clue in The Guardian
O
L
D
W
O
R
L
D
Buddy explains!
The straight part
We know that "region, excluding America" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case region, excluding america = old world.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does OLD WORLD mean?
OLD WORLD adjective- Of, or relating to the ancient world or former times