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Webster 1913 Edition

(?; 135)

Noun.

Confinement to a sick bed, or time of taking to one’s bed from sickness.

Boyle.

(Astrol.)

Aspect of the heavens at the time of taking to one's sick bed, by which the prognostics of recovery or death were made.

, n.

The time at which a person takes to his bed in a disease.

In astrology, the scheme or aspect of the heavens, by which the prognostics of recovery or death are discovered.

decumbiture ‎(plural decumbitures)

(obsolete) The fact of lying down, specifically of a person due to illness.
- 1734, William Stukeley, Of the Gout, J. Roberts, page 34:
  It happened during my tedious and melancholy decumbiture...
(astrology, now historical) The time one takes to one's bed during an illness, as used for astrological prognostications; or a chart drawn up to express this.
- 1971, Keith Thomas, Religion and the Decline of Magic, Folio Society 2012, p. 277:
  By casting a figure for the decumbiture, or moment when the patient felt ill, and by resolving a question on the sight of his urine, the astrological doctor claimed to be able to diagnose the disease, prescribe the treatment, foretell when the sickness would reach its crisis, and prognosticate its eventual outcome.