The most common and most likely answer to this crossword clue is the 6 letter word ACCORD
I've seen this crossword clue in Financial Times
A
C
C
O
R
D
More clues leading to the result ACCORD
- A line about Churchill's first agreement
- Correspondence course's leader wearing a tie
- A cable containing conservative agreement
- At heart back company road agreement
- Billattached to Democrat correspondence
- A group of notes read out in agreement
- Notes on string producing harmony
- Men in Civil Defence backing current agreement
- Account with line suggesting agreement
- Bill firm over road agreement
Buddy explains!

The straight part
We know that "harmony" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case harmony = accord.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 ACCORD mean?
ACCORD noun- Agreement or concurrence of opinion, will, or action.
- A harmony in sound, pitch and tone; concord.
- Agreement or harmony of things in general.
- An agreement between parties in controversy, by which satisfaction for an injury is stipulated, and which, when executed, prevents a lawsuit.
- An international agreement.
- Assent
- Voluntary or spontaneous impulse to act.
- To make to agree or correspond; to suit one thing to another; to adjust.
- To bring (people) to an agreement; to reconcile, settle, adjust or harmonize.
- To agree or correspond; to be in harmony; to be concordant.
- To agree in pitch and tone.
- To grant as suitable or proper; to concede or award.
- To give consent.
- To arrive at an agreement.