Definition of hour-glass:
(n) :
(time) A unit of time of one twenty-fourth of a day (sixty minutes).
(n) :
A season, moment, or time.
(n) :
(poetic) The time.
(n) :
(chiefly in the plural) The amount of labor demanded by an employer in terms of time.
(n) :
(military, in the plural) Used after a two-digit hour and a two-digit minute to indicate time.
(n) :
(Christianity, in the plural) The set times of prayer, the canonical hours, the offices or services prescribed for these, or a book containing them.