  We undertake to develop a successful framework for commutative-associative
hypercomplex numbers with the view to explicate and study associated geometric
and generalized-relativistic concepts, basing on an interesting possibility to
introduce appropriate multilinear metric forms in the treatment. The scalar
polyproduct, which extends the ordinary scalar product used in bilinear
(Euclidean and pseudo-Euclidean) theories, has been proposed and applied to be
a generalized metric base for the approach. A fundamental concept of
multilinear isometry is proposed. This renders possible to muse upon various
relativistic physical applications based on anisotropic {\it versus} ordinary
spatially-rotational case.
