What is "establishment of the port"

Establishment \Es*tab"lish*ment\, n. [Cf. OF. establissement, F.

1. The act of establishing; a ratifying or ordaining; settlement; confirmation.

2. The state of being established, founded, and the like; fixed state.

3. That which is established; as:

   1. A form of government, civil or ecclesiastical; especially, a system of religion maintained by the civil power; as, the Episcopal establishment of England.

   2. A permanent civil, military, or commercial, force or organization.

   3. The place in which one is permanently fixed for residence or business; residence, including grounds, furniture, equipage, etc.; with which one is fitted out; also, any office or place of business, with its fixtures; that which serves for the carrying on of a business; as, to keep up a large establishment; a manufacturing establishment.

      Exposing the shabby parts of the establishment.
      --W. Irving.

      Establishment of the port (Hydrography), a datum on which the tides are computed at the given port, obtained by observation, viz., the interval between the moon's passage over the meridian and the time of high water at the port, on the days of new and full moon.

n. (context hydrography English) A datum on which the tides are computed at the given port, obtained by observation. It is the interval between the Moon's passage over the meridian and the time of high water at the port, on the days of new moon and full moon.