How many letters does the top answer for “a systematic interpretation or explanation of a specific topic” have?

The most common answer is exposition (10 letters).

Crossword clue: a systematic interpretation or explanation of a specific topic

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

exposition 10 letters wn-def

a systematic interpretation or explanation of a specific topic

expounding 10 letters wn-def

a systematic interpretation or explanation of a specific topic