Contiguity, n.
Etymology: [Cf. F. contiguit, LL. contiguitas.]
The state of being contiguous; intimate association; nearness; proximity. The convicinity and contiguity of the two parishes. T. Warton.
Shades of meaning
Fernald has no entry of its own for contiguity; he lists it under approximation.
He lists it without comment; the entries above explain its neighbors.