The most common and most likely answer to this crossword clue is the 5 letter word INCUS
I've seen this crossword clue in Independent
I
N
C
U
S
More clues leading to the result INCUS
- Bone is broken by northern copper
- Small bone found in pin cushion
- Suffers, after removal of right bone
- Bone idle new carer under supervision initially
- One magnet’s orientation to hold copper for anvil
- Incorporated America — it helps to listen
- Anvil’s casing of iron — copper’s added
- Like an anvil, more than half banged up?
- Tiny bone is inlaid with new copper
Buddy explains!

The straight part
We know that "bone" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bone = incus.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 INCUS mean?
INCUS noun- A small anvil-shaped bone in the middle ear.
- An accessory cloud, in the shape of an anvil which forms by spreading at the top of a cumulonimbus.