"Economic moat" is a term coined by investor Warren Buffet. It means how susceptible a company is to competition by other companies. Coca-Cola and Phillip Morris (Marlboro cigarettes) are companies with wide economic moats because of the popularity and consumer loyalty of their marquee brands. Boeing has a narrow but deep economic moat because its 777 and 787 aircraft are not subject to immediate displacement, but companies like Airbus and Bombardier could play catch-up over the course of several years by developing similar models that would threaten their primacy. That would close the moat.
-- "Give me an example of a company with a wide economic moat."
-- "The local water company, because no competitor can rush right in with a distribution system (pipes)."
-- "Besides, who else is gonna fill that moat? lol."