Team work is the ability for any group to work with a common goal.
If you are a professionally working somewhere you might have noticed that no work is accomplished without the team.In other words, man is interdependent on the other to complete any task wherever you go.Its a common human tendency.
Take a doctor for example, he can never operate all alone, or he hardly takes individual decisions. Knowledge and skills have to be shared for saving the patient's life.
If it is a professional organization you are working in, if you are given a project you are given for your team not you individual alone.
Each one may be skilled in one thing or the other. Taking every inch of useful skill from every other brains to accomplish your task is termed as team work.
Reports through ages ave shown that the percentage of success achieved by team work is far far higher than success achieved by individual member in a group.
How do you think big giants like Infosys, Wipro and many others have come up as world IT leaders? Its not an individual effort. It is again the team work that established the company and still gets it going under high profits.