How many letters does the top answer for “an event that might have been arranged although it was really accidental” have?

The most common answer is coincidence (11 letters).

Crossword clue: an event that might have been arranged although it was really accidental

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

coincidence 11 letters wn-def

an event that might have been arranged although it was really accidental

happenstance 12 letters wn-def

an event that might have been arranged although it was really accidental