In plain English
A moat helps a company keep its position when competitors try to win its customers. It might come from a trusted brand or distribution relationships that are difficult to recreate. The important question is how hard that advantage is to copy or overcome, and how long it can last.
Example
A startup has long-term distribution relationships that give it access to customers competitors struggle to reach. If those relationships sustain its competitive advantage, they could form part of its moat.