The tetrad for the perfect figure—the cube, length, depth, and width.
Having sent for that Brhman, he learnt from him a tetrad of gths.
They are aborting members of the tetrad, and appear to have been used as food by the other spores.
Such an axis of symmetry is known as a tetrad axis of symmetry.
If the second cell division plane is formed at right angles to the first, a cell surface or tetrad is formed.
The four cocci which result from a single division may remain together, giving the tetracoccus or tetrad grouping.
They are parallel to the edges of the cube, and in the different classes coincide either with tetrad or dyad axes of symmetry.
There are five axes of symmetry, one tetrad and two pairs of dyad, each perpendicular to a plane of symmetry.
The elements of symmetry are a tetrad axis with a plane perpendicular to it, and a centre of symmetry.
Here there are two pairs of vertical planes of symmetry intersecting in the tetrad axis.