DICTIONARY OF AVIATION 127
place : distinguisht as the astronomical, celestial, mathe- matical, rational, real, or true horizon.
geographical horizon, the great circle en the earth's sur- face in the plane of the celestial or astronomical horizon.
oblique horizon, the celestial horizon of any place be- ticeen the equator and either pole.
right horizon, the celestial horizon of a place en the equator of the earth, the plane of tuhich is perpendicular to the plane of the eqinexial.
horizon-Less ha'zai-zan-las adj. having no definit horizon; visually boundless.
horizon-line ha'zai-z9n,}ain n. the line of the horizon; the horizon.
horizontal ,hezi'zentt adj. parallel to the plane of the hori- zon; level, flat.
horse-power 'heizs^au-az n. [also spelt horsepower] the power or rate of work of a horse in drawing; (in mechan- ics) a unit for mesuring the work of a motor, usually 550 foot-pounds per second (or about one and one^third times the actual power of an average herse).
horsetail 'he:zs,teel n. a ferm of cirrus cloud resembling a horse's tail; mare's-tails.
hot-windy 'het,wmdi adj. (in Australia") characterized by the presence of het winds, see under wind.
house hauz tr. put away in a house or shed; place under cover; shelter: as, methods of *housmg balloons.
house-top 'haus,tep n. the tep of a house; roof.
hover 'hAvaz v.
1. intr. hang or remain suspended in the air over, above, or about a particular place or spot, with or without the flapping of wings, especially when preparing to dart or siuoop in some direction; float or remain suspended in air.
2. tr. (obsolete) flap or flutter (the wings), so as to main- tain itself in the air, as a bird sometimes does.
hover 'hAV9z: n. an act of hovering, as that of a bird.
hoyerer 'hAva-zaz n. a creature or thing that hovers in the air; specifically, any bird that habitually hovers, or prac- tises hovering flight.
hovering 'hAV9-zir) n. an act of hovering; the action or con- dition of hovering; suspension or poising in the air, as with fluttering or outstjetcht wings.
hull hAl n. the frame or bedy of a dirigible; the floatevessel of an airship : as, an aluminum *hull divided into sixteen gastight compartments.
hull-resistance 'hAl-zr,zistns n. the resistance which the hull, bedy, frame or car of a balloon, airship, or flyer,
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