The quality of being cogent; the power to compel conviction or agreement through force of argument or evidence.
From Latin 'cogentia' derived from 'cogere' (to compel together, from co- + agere). The quality of being cogent meaning compelling or convincing.
The word 'cogence' is vanishingly rare compared to 'cogency'—both mean the same thing, but language tends to standardize on one form, and 'cogency' won that evolutionary battle by a landslide.
Complete word intelligence in one call. Free tier — 50 lookups/day.