A business as a castle; its competitive advantages as the moat around it — the wider and deeper, the harder for competitors to storm the walls.
Buffett didn’t invent the concept — sustainable competitive advantage is the subject of Michael Porter’s 1980 Competitive Strategy — but he gave it a name that stuck, using “moat” in Berkshire Hathaway shareholder letters more than 20 times since 1986. A moat isn’t a temporary lead; it’s a structural reason competitors can’t simply copy what works, whether that’s network effects, brand, switching costs, or scale.
Worth being precise about the citation tier here: there is no peer-reviewed paper titled on “economic moats” specifically. The primary sources are Buffett’s own letters (practitioner) and Porter’s foundational strategy theory (also practitioner-facing, though foundational to the academic strategy field that followed it) — an honest, lower-tier sourcing situation, not a gap to paper over.