The most common and most likely answer to this crossword clue is the 5 letter word BOSON
B
O
S
O
N
More clues leading to the result BOSON
Buddy explains!
The straight part
We know that "Something very small" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case something very small = boson.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 BOSON mean?
BOSON noun- A particle with totally symmetric composite quantum states, which exempts them from the Pauli exclusion principle, and that hence obeys Bose-Einstein statistics. They have integer spin. Among them are many elementary particles, and some (gauge bosons) are known to carry the fundamental forces. Compare fermion.
- A boatswain.