what do you mean by unit vectors?

Unit Vectors:

A vector of unit magnitude is called a unit vector . It has the same direction as that of the given vector .

A unit vector of  is written as and is read as A cap.

= A  Or

 = 

 where A = magnitude of .

So, a unit vector in a given direction can also be defined as a vector in that direction divided by the magnitude of the given vector.

It has not unit and dimension. It represents direction only.

Example-  are the unit vectors along x axis , y axis and z axis respectively.