title: DDD, Is domain model a domain or a sub-domain
body: <p>These terms make me confuse, please help me understand it a little bit more. So what exactly is a <strong>Domain</strong> in DDD. So my understanding is, <strong>Domain</strong> is an entity or a class in my code and I start asking myself what is the sub-domain then? I want to give an example of an e-commerce system. Here's how I define each term.</p>
  <pre><code>// My understanding is, this class is a domain. 
  // So domain model is actually a domain living inside of e-commerce bounded context.
  
  package io.joseph.e-commerce.domain;
  
  class ShoppingCart {
    private String shoppingCartId;
  }
  </code></pre>
  <p>but yeah I think I miss understanding something since I don't know what is the sub-domain here.</p>