Quiescence, Quiescency, n.
Etymology: [L. quiescentia, fr. quiescens, p. pr.; cf. F. quiestence. See Quiesce.]
The state or quality of being quiescent. "Quiescence, bodily and mental." H. Spencer. Deeds will be done; -- while be boasts his quiescence. R. Browning.
Shades of meaning
Fernald has no entry of its own for quiescence; he lists it under rest.
He lists it without comment; the entries above explain its neighbors.