Context is a very important thing to understand if you want to be a
good archaeological detective.  Context is what archaeologists depend on,
it is what makes us so very different from people who rob sites
just for the 'neat' stuff they may find.
You see, context allows us to understand way more about artifacts.
The context of an artifact is discovered when we see where
an artifact was left and what it was left nearby.
It can give us clues as to what used to be near the object in the past.
If we look at the pattern of the way artifacts are left on the site we may be
able to understand more of what was going on.
For example, if we find bowls and stones used to grind food in one area,
a hearth nearby, a few postholes and then some rock flakes from where
stonetools were made, we may be able to understand that the site was
a house which had a food preparation area (kitchen),
a living room (hearth) and tool making area.
If all we could see was the stone tool making area, we might not
even know that people lived here.
Or, if someone stole all the food bowls we would not think
that people who lived there in the past cooked or ate here and so,
we would probably not think of it as a house settlement.
Does this make sense? When we look at context we are able to see the relationships between different artifacts, ecofacts and features that we find.  If we don't have the context we might not see the whole picture clearly.
Imagine that you are an archaeologist digging away and you come across a large jar.
This jar could have been made for many purposes, you don't know which.
 BUT.... if you look at the context of the jar, the
clues might let you be able to figure it out.
Let's picture two cases and you try and guess what the jar was used for:
Case 1. You find a large clay jar.  Around it you can see many others that
are exactly the same.  They are all together in one area of the site,
nowhere else do you find any other  jars.
What do you think this large jar could have been used for? Examine the context.
Case 2. You find another large clay jar.  Nearby is a hearth and other jars.  All of the jars have blackened bottoms from the fire.
What do you think this large jar could have been used for? Examine the context.
Think about this for a few minutes then skip down the page and see if you guessed right!
Well, in Case 1, I would guess that the jar was used for storage.
 I thought this because there was quite a few of them and they were
all placed together, just like we stock our cans in the pantry.
In Case 2, I would guess that the jar was used for cooking.
I thought this because the bottom was blackened so it had been used over a fire.
Evidence of a fire came from the hearth feature which was nearby.
Now imagine a third case. You are working as an archaeological detective, you are the best in the world.  Someone knocks on your door one day and brings you a large jar.  They want to know all about it.  Unfortunately, you have no context, so all you can say about the artifact is that it is a jar - whoopdedoo !!!
As we can see, context is very important in archaeology.
This is why it is so
sad and terrible when people rob sites or just pick up
artifacts off the ground.  Once this is done, all the context is lost.