δυειδής
From LSJ
ἁρμονίη ἀφανὴς φανερῆς κρείττων → the hidden attunement is better than the obvious one, invisible connection is stronger than visible, harmony we can't see is stronger than harmony we can, unseen harmony is stronger than what we can see
English (LSJ)
δυειδές, of the class of the dyad, μεσότης Dam.Pr.189.
Spanish (DGE)
v. δυοειδής.