The most common and most likely answer to this crossword clue is the 6 letter word COPULA
I've seen this crossword clue in The Times
C
O
P
U
L
A
Buddy explains!
The straight part
We know that "Bond" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bond = copula.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 COPULA mean?
COPULA noun- (grammar) A word, usually a verb, used to link the subject of a sentence with a predicate (usually a subject complement or an adverbial), that unites or associates the subject with the predicate.
- A function that represents the association between two or more variables, independent of the individual marginal distributions of the variables.
- A device that connects two or more keyboards of an organ.
- The act of copulation; mating.