simplex

noun
  1. 1

    An analogue in any dimension of the triangle or tetrahedron: the convex hull of n+1 points in n-dimensional space.

  2. 2

    A simple word, one without affixes.

adjective
  1. 1

    Single, simple; not complex.

  2. 2

    Unidirectional

Source: https://en.wiktionary.org/wiki/simplex