The most common and most likely answer to this crossword clue is the 11 letter word MORTARBOARD
I've seen this crossword clue in Financial Times
M
O
R
T
A
R
B
O
A
R
D
More clues leading to the result MORTARBOARD
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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 MORTARBOARD mean?
MORTARBOARD noun- A square board, with a handle, on which mortar or plaster is carried: a hawk.
- An academic cap that has a flat square top with a tassel.