Wikipedia defined it more clearly as a concept of people working together cooperatively, as in a sports team.
As for me, I defined it as a group of people that have same hobby and dream moving towards a same direction.
The company said "Let us fight for a 100 million sales this year, by our teamwork we can do it". The director looking at the 100 million money, but the worker looking at 100 million job. So it will fail and not to mansion about teamwork.
The company said "Let us fight for a 100 million sales this year, by our teamwork we can do it and if we achieve it, I will share 1% of the profit". This time the director looking at the 100 million money, and some worker looking at 1% profit but some still cleaver enough looking at the 100 million job. So it have some changes to success. From here we can see the effect of teamwork.
The company said "Let me be your partner and we fight for a 100 million sales this year, by our teamwork we can do it. We share whatever profit that we make this year". This time, the director and the worker are looking at the 100 million money. So it mostly will success.
Same dream, same direction, that what I call teamwork.
A joke from internet
There were four people named
Everybody, Somebody, Anybody and Nobody.
There was an important job to be done and
Everybody was asked to do it.
Everybody was sure Somebody would do it,
Anybody could have done it but Nobody did it.
Somebody got angry about that, because it was
Everybody thought Anybody could do it but
Nobody realized that Everybody wouldn't do it.
It ended up that Everybody blamed Somebody
when Nobody did what Anybody could have done.