The most common and most likely answer to this crossword clue is the 6 letter word CAECUM
I've seen this crossword clue in The Guardian
C
A
E
C
U
M
More clues leading to the result CAECUM
Buddy explains!
The straight part
We know that "on the 11 25/on the 11 25" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case on the 11 25/on the 11 25 = caecum.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 CAECUM mean?
CAECUM noun- A blind pouch connected to the large intestine between the ileum and the colon.