What is the definition of dimension ?
What is dimension?
Dimension, in physics, of a physical quantity is the index of each of the fundamental quantity ( Length, mass, time, temperature, Luminous intensity, Current ) which expresses that quantity.
For example, the dimension of speed can be derived in the following way:
The above expression tells you the dimension of "speed".
In its dimension, there is no mention of mass, current or temperature because they don't play any role in defining this quantity. Or, you could say the dimension of mass in this expression is zero, that of current , luminous intensity, temp too is zero.
In a completely different sense, dimension is about the space an object takes up. It signifies length, breadth, and height/thickness of the physical object which occupies space.
So the dimensions of a brick could be expressed as 20cm*10cm*6cm.