(Geol.) An epoch at the close of the Canadian period of the American Lower Silurian system; -- so named from a township in Clinton Co., New York. See the Diagram under Geology. [ 1913 Webster ]

(Geol.) An epoch at the close of the American lower Silurian system. The rocks are well developed near Cincinnati, Ohio. The group includes the Hudson River and Lorraine shales of New York. [ 1913 Webster ]

n. [ LL. epocha, Gr. 'epochh` check, stop, an epoch of a star, an historical epoch, fr. 'epe`chein to hold on, check; 'epi` upon + 'e`chein to have, hold; akin to Skr. sah to overpower, Goth. sigis victory, AS. sigor, sige, G. sieg: cf. F. époque. See Scheme. ] 1. A fixed point of time, established in history by the occurrence of some grand or remarkable event; a point of time marked by an event of great subsequent influence; as, the epoch of the creation; the birth of Christ was the epoch which gave rise to the Christian era. [ 1913 Webster ]

In divers ages, . . . divers epochs of time were used. Usher. [ 1913 Webster ]

Great epochs and crises in the kingdom of God. Trench. [ 1913 Webster ]

The acquittal of the bishops was not the only event which makes the 30th of June, 1688, a great epoch in history. Macaulay. [ 1913 Webster ]

☞ Epochs mark the beginning of new historical periods, and dates are often numbered from them. [ 1913 Webster ]

2. A period of time, longer or shorter, remarkable for events of great subsequent influence; a memorable period; as, the epoch of maritime discovery, or of the Reformation. “So vast an epoch of time.” F. Harrison. [ 1913 Webster ]

The influence of Chaucer continued to live even during the dreary interval which separates from one another two important epochs of our literary history. A. W. Ward. [ 1913 Webster ]

3. (Geol.) A division of time characterized by the prevalence of similar conditions of the earth; commonly a minor division or part of a period. [ 1913 Webster ]

The long geological epoch which stored up the vast coal measures. J. C. Shairp. [ 1913 Webster ]

4. (Astron.) (a) The date at which a planet or comet has a longitude or position. (b) An arbitrary fixed date, for which the elements used in computing the place of a planet, or other heavenly body, at any other date, are given; as, the epoch of Mars; lunar elements for the epoch March 1st, 1860.

Syn. -- Era; time; date; period; age. -- Epoch, Era. We speak of the era of the Reformation, when we think of it as a period, during which a new order of things prevailed; so also, the era of good feeling, etc. Had we been thinking of the time as marked by certain great events, or as a period in which great results were effected, we should have called the times when these events happened epochs, and the whole period an epoch. [ 1913 Webster ]

The capture of Constantinople is an epoch in the history of Mahometanism; but the flight of Mahomet is its era. C. J. Smith. [ 1913 Webster ]

‖n. [ L. ] See Epoch. J. Adams. [ 1913 Webster ]

a. Belonging to an epoch; of the nature of an epoch. “Epochal points.” Shedd. [ 1913 Webster ]

(Geol.) The closing subdivision of the Hamilton period in the American Devonian system; -- so called because the formations of this period crop out in Genesee, New York. [ 1913 Webster ]

[ From Medina in New York. ] (Geol.) A subdivision of the Niagara period in the American upper Silurian, characterized by the formations known as the Oneida conglomerate, and the Medina sandstone. See the Chart of Geology. [ 1913 Webster ]