Tensor
From Conservapedia
Vectors and matrices are examples of more general objects called tensors. Tensors are defined via their transformation properties: suppose we have a set of numbers vi, and we want to know how their values change under rotation of Cartesian axes. If the values in the new co-ordinate system v'i can be written
v'i = Lijvj
where Lij are the elements of a rotation matrix then the vi are said to be the components of a rank one tensor. Similarly, the components of a rank two tensor satisfy
a'ij = LimLjnamn
and for higher order tensors, we just keep adding more of the Lij rotation matrices. Scalars, vectors and matrices are rank zero, rank one and rank two tensors respectively.
