Dictionary.net

of Die

Hemera, A day, (F.) Jour. The day is, properly, the period during which the solar light illumines our horizon: but commonly, also, we designate by the word day the period of 24 hours or Nycthemeron, which is frequently divided into four parts -morning, midday, evening, and midnight. In antiquity, great importance was attached to the observation of days in disease. The medical day is usually reckoned at 24 hours, -universally, in estimating the duration of a disease. In parts of the United States, it comprises only the time when the sun is above the horizon, as regards the administration of medicine, so that if a medicine be ordered to be taken four times day, it is understood to mean during the 12 hours of day.

A day. [Lat.]