The most common and most likely answer to this crossword clue is the 4 letter word RHOS
R
H
O
S
Buddy explains!
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 RHOS mean?
RHOS noun- The seventeenth letter of the Modern Greek and Classical alphabets and the nineteenth letter of Old and Ancient.
- The sensitivity of the option value to the risk-free interest rate.