In vector algebra, there is a quantity called a "Unit Vector" and it is defined as "A vector of length 1".
However the product of a vector multiplied by a scalar is a vector and a vector multiplied by a another vector is also a vector. An example of vector algebra is Faraday's Law which relates three vectors: The magnetic field, the motion of the conductor, and the induced voltage and current.
So if we know the result of a vector operation is another vector quantity, then a unit vector seems to be a superfluous concept. It's like having a "Unit Mass Of 1" or "Unit Weight Of 1", a "Unit Dollar of 1" that you multiply to get the actual mass, weight, or a dollar amount.
However the product of a vector multiplied by a scalar is a vector and a vector multiplied by a another vector is also a vector. An example of vector algebra is Faraday's Law which relates three vectors: The magnetic field, the motion of the conductor, and the induced voltage and current.
So if we know the result of a vector operation is another vector quantity, then a unit vector seems to be a superfluous concept. It's like having a "Unit Mass Of 1" or "Unit Weight Of 1", a "Unit Dollar of 1" that you multiply to get the actual mass, weight, or a dollar amount.