The most common and most likely answer to this crossword clue is the 8 letter word EUROPIUM
I've seen this crossword clue in The Guardian
E
U
R
O
P
I
U
M
More clues leading to the result EUROPIUM
Buddy explains!

The straight part
We know that "EU" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case eu = europium.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 EUROPIUM mean?
EUROPIUM noun- A metallic chemical element (symbol Eu) with an atomic number of 63.