The most common and most likely answer to this crossword clue is the 7 letter word ANALOGY
I've seen this crossword clue in The Sunday Telegraph
A
N
A
L
O
G
Y
More clues leading to the result ANALOGY
- Initially advise voter against keeping record in correspondence
- A refusal to keep diary, or something similar
- Any envelope for a record correspondence?
- Express an aversion for relation?
- A vote against retaining record correspondence
- Correspondence arising from a record in a city
- A diary kept in whatever relationship helping to explain
- Similarity of nearly everyone in agony suffering
Buddy explains!

The straight part
We know that "relationship helping to explain" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case relationship helping to explain = analogy.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 ANALOGY mean?
ANALOGY noun- A relationship of resemblance or equivalence between two situations, people, or objects, especially when used as a basis for explanation or extrapolation.
- The proportion or the equality of ratios.
- (grammar) The correspondence of a word or phrase with the genius of a language, as learned from the manner in which its words and phrases are ordinarily formed; similarity of derivative or inflectional processes.