What does it mean for a figure to be 3-dimensional?

[no idea]

When i am in a 3 dimensional space, can i see any 3 - dimensional figure?
and actually i do not much know about what is 3 dimensional . Could anyone explain it further please?THx

 

[Math Is Hard]

You know what length, height and width are, right? There you have it.

 

[no idea]

oh thanks . then how about 4d ?

 

[arildno]

We cannot percieve more than 3 spatial dimensions.

 

[VantagePoint72]

The fourth dimension is time. While we can't perceive anything above the three common spatial dimensions and the temporal dimensions, superstring theory calls for 10 dimensions (9 spatial, 1 temporal) and M-theory calls for even more. While neither of these theory of everything candidates has been proven (actually, M-theory is just a more robust form of superstring theory so technically they're the same), the evidence is convincing. We "see" these extra dimensions in terms of disturbances in them, i.e. what we call forces. They would explain the four fundamental forces and the dimensions beyond 4 could escape our notice by being "curled up". It's an interesting Universe we live in.