Full Idea
Just as day is in many places at once, but not separated from itself, so each idea might be in all its participants at once.
Gist of Idea
Each idea is in all its participants at once, just as daytime is a unity but in many separate places at once
Source
Plato (Parmenides [c.366 BCE], 131b)
Book Reference
Plato: 'Plato IV (Cratylus,Parmenides,Hippias Maj, Min)', ed/tr. Fowler,H.N. [Harvard Loeb 1926], p.215