The state or quality of being coinstantaneous; perfect simultaneity.
From coinstantaneous + -ness (suffix forming abstract nouns). A rare, highly formal noun expressing the philosophical concept of exact temporal overlap.
This is what you get when philosophers want to talk about the absolute precision of time—not 'happening together' but 'happening with no possible time gap whatsoever.' Quantum mechanics finally gave this word real relevance.
Complete word intelligence in one call. Free tier — 50 lookups/day.