After listening to Warren Buffett's shareholders meeting at Omaha, I begun to get acquainted with the word "moat". The word "moat" means the river which protect the castle from enemies. In the business world, every company have to protect themselves, and the economic moat is the way they protect themselves.
Here is the list that the economic moats I discovered from observation and reading:
Brand, big names, belief: makes customer think that xx brand is good. e.g. Coca Cola
cost advantage: lower price can make competitors really uncomfortable. e.g. Costco
switching cost: it costs a lot for customers to change a product or service. e.g. Apple
Entry barriers: hard for new company to entry the market. e.g. TSMC
Monopoly or Oligopoly: often comes with high entry barriers. e.g. Visa
Economic of scale: hard for new company to compete. e.g. Meta
Intangible asset: tech edge, patent, license, permits that can drive out competitors. e.g. TSMC