A moat is a durable competitive advantage that protects a company from competition over time. Popularized by Warren Buffett as a metaphor for structural defenses surrounding a business (like a moat surrounding a castle), the main categories are network effects (value increases with each additional user), scale economies (larger competitors have cost advantages smaller ones can't match), brand (customers prefer the trusted name even at higher prices), switching costs (customers find it expensive or painful to leave), regulatory (licenses, certifications, compliance position), and proprietary technology (defensible IP or unique capability). The discipline is honestly assessing whether a company has a real moat or just temporary advantage...