The most common and most likely answer to this crossword clue is the 5 letter word TIARA
I've seen this crossword clue in The Daily Telegraph
T
I
A
R
A
More clues leading to the result TIARA
- Headdress so long one wears
- Headdress seen in trip abroad oddly
- Jewellery I found in Scarlett’s place
- Contribution for dementia raising maybe half a crown
- I'm off to grab one item of headgear
- Jewelled head dress, one worn by groups of soldiers
- Trip abroad, oddly to see what Pope wears
- A scoundrel returned to snatch one crown
- Headdress that's so long when one puts it on
- Stones’ backing band needs so long to tour India
Buddy explains!

The straight part
We know that "crown" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case crown = tiara.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 TIARA mean?
TIARA noun- The papal crown.
- An ornamental coronet.