The most common and most likely answer to this crossword clue is the 3 plus 4 letter word BIG BANG
I've seen this crossword clue in The Guardian
B
I
G
B
A
N
G
More clues leading to the result BIG BANG
- Moment one monster and knight devoured by witch
- Singer accepts this country artist's first original idea?
- Book one group including bass for a stellar opening?
- Creation of independent Great Britain stops crash
- Important fringe event starting time?
- Very important American fringe initiation theory?
- Cosmic event covered in large report
- Origin of all that’s heard on 5th Nov?
- Successful fringe the start of our expansion?
- Universal beginning and end for 1 across 12
Buddy explains!
The straight part
We know that "the start of our expansion" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case the start of our expansion = big bang.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.