Comment by Ibrahim Tanyalcin on "How would you explain objects and arrays in JavaScript to those who have just started programming?"

Both are entities to store any type of value (primitives (string,boolean,number), function, object, null and undefined).
Both store the value with 'keys'
In objects and arrays keys are (coerced to) strings
The order of keys are not important on objects, one should not rely on key order
Arrays are specialized kind of objects where keys are Numbers (coerced to strings) and the order of keys are important and preserved.
Therefore, for the above reason there is something called sparse Arrays (missing keys). But there is no equivalent sparse "Object".
Array constructor is an instance of Object constructor but not vice versa (all arrays are objects, but not all objects are arrays)
For the above reason Arrays have special methods down the prototype chain such as reduce,map,forEach etc..

These are some rough headlines that comes to mind which I think can help.

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