The most common and most likely answer to this crossword clue is the 7 letter word HARMONY
H
A
R
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Y
More clues leading to the result HARMONY
Buddy explains!

The straight part
We know that "concord" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case concord = harmony.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 HARMONY mean?
HARMONY noun- Agreement or accord.
- A pleasing combination of elements, or arrangement of sounds.
- The academic study of chords.
- Two or more notes played simultaneously to produce a chord.
- The relationship between two distinct musical pitches (musical pitches being frequencies of vibration which produce audible sound) played simultaneously.
- A literary work which brings together or arranges systematically parallel passages of historians respecting the same events, and shows their agreement or consistency.
- Agreement or accord.
- A pleasing combination of elements, or arrangement of sounds.
- The academic study of chords.
- Two or more notes played simultaneously to produce a chord.
- The relationship between two distinct musical pitches (musical pitches being frequencies of vibration which produce audible sound) played simultaneously.
- A literary work which brings together or arranges systematically parallel passages of historians respecting the same events, and shows their agreement or consistency.