Tropical Cyclone. Meteorological depression originating in low latitudes.
Tropical Month. Interval between successive transits of Moon through the same point in Ecliptic. Value is 29 d 12h 43-075 m.
Tropical Year. Time taken by Earth to go round Ecliptic from First Point of Aries. As First Point of Aries has a variable retrograde motion (about 50-26" annually), Earth does not
complete a sidereal revolution. Length is about 365 d 05 h 48 m 48 s, but this varies slightly.
Tropic of Cancer.Parallel of latitude, or declination, 23° 27' N, being the highest parallel reached by Sun in his northerly motion. Reached about June 21.
Tropic of Capricorn. Parallel of latitude, or declination, 23° 27'S, being the highest parallel reached by Sun in his southern motion. Reached about December 21.
Tropics. The tropics of Cancer and Capricorn. The area of Earth between the tropics.
Tropic Tides. Diurnal tides whose amplitudes vary with the declinational values of the tide-raising bodies-Sun and Moon.
Tropopause. Boundary between the troposphere and stratosphere.
Troposphere. The atmospheric shell in which we live. Extends upwards to a height of about 10 miles in the tropics, about seven miles in temperate latitudes, perhaps, five miles at poles. Temperature decreases, more or less uniformly, with heights. Winds are not constant, rain can be precipitated.
Trot. Line of mooring buoys laid out at regular intervals. 2. Line of fishing hooks laid out at regular intervals when 'bottom fishing'.
Trough 365 Trysail Mast
Trough. Hollow between two waves in water. 2. Area of lowest barometric pressure in a cylonic storm, lying perpendicularly- more or less - to direction of travel of the storm.
Truck. Circular piece of wood fitted on head of an uppermost mast. Generally carries flag halliards, sometimes a wind vane.