bivium

Etymology
.

Noun

 * 1)  One side of an echinoderm, including a pair of ambulacra, in distinction from the opposite side, which includes three ambulacra.

Etymology
Substantive from, which is derived from.

Noun

 * 1) A place with or where two ways meet; fork in the road, crossroad.
 * 2) A pair of alternative means or methods.