Propinquity, n.
Etymology: [L. propinquitas, from propinquus near, neighboring, from prope near.]
1. Nearness in place; neighborhood; proximity.
2. Nearness in time. Sir T. Browne.
3. Nearness of blood; kindred; affinity. Shak.
Shades of meaning
Fernald has no entry of its own for propinquity; he lists it under approximation.
Where he writes about it:
Nearness, neighborhood, and propinquity are commonly used of place; approximation, of mathematical calculations and abstract reasoning; we speak of approach to the shore, nearness to the town, approximation to the truth. — from approximation