From A Word a Day (one of my favorite sites):
This week's theme: words with double connections.
didymous (DID-uh-muhs) adjective
Occurring in pairs; twin.
[From Greek didymos (twin). Ultimately from the Indo-European root dwo- (two)
that also gave us dual, double, dubious, doubt, diploma, twin, and between.]
-Anu Garg (words at wordsmith.org)
"Shakespeare portrays the didymous functionaries as if they were
a unit comprised of two parts."
Peter Usher; Hamlet's Universe; Aventine Press; 2006