Good principles to explain the use of data objects

Question

I'm in a little need of names clarification. First a brief description of my position. I prepare as debutant giving a junior developer job descriptions, which also provided another perspective on how important communication is, and to put it beyond doubt.

Simply; I like to understand what he mean with "Context" and I like to give a adopted description of what a POCO is. Now, this is not the exactly problematic words. We haven't even spoken yet. I describe it more as the semantic problem and focus on data and IoC, because there is the place we're going to met (He = GUI, I'm BL).

I give a manual-typed sample just as a reference for naming different part of it. Some terms are local to a Manufacturer or tool and some are used more Generic, which I prefer the latter.

// Poco, Model?
public class Customer
{
    public int CustomerId { get; set; }
    public string Name { get; set; }
}


// A short sign of repository pattern
public class CustomerContext
{

   // Is this a context or even a entity? 
   List<Customer> cust;
   public CustomerContext()
   {
      cust = new List<Customer>();
      cust.Add(new Customer() { CustomerId = 1, Name = "Doe" });
      cust.Add(new Customer() { CustomerId = 2, Name = "John" });
      cust.Add(new Customer() { CustomerId = 3, Name = "Zelda" });
      cust.Add(new Customer() { CustomerId = 4, Name = "Kim" });
   }

   public IQueryable<Customer> Get()
   {
      return cust;
   }
}

*What terms fit best? *

Are 'Customer' a Model (tooked from MVC)? Does we, simply put, mean the same with POCO?

What do I call the sample typed data above? Mocks? Simply "Data"?

What do I call the object CustomerContext? A repository? A Context? Is it an Entity?

Are there other terms that have escaped this scope?

It appears common to write about repositories and generics, even though fell into a scope of a manufacturer (where i.e. 'Entity' commonly means Entity Framework). A strong indication of what terms means what (and when), would be of help.