Main Entry: ho·ri·zon

Pronunciation: \hə-ˈrī-z^ən\

Function: noun

Etymology: Middle English orizon, from Late Latin horizont-, horizon, from Greek horizont-, horizōn, from present participle of horizein to bound, define, from horos boundary; perhaps akin to Latin urvum curved part of a plow

Date: 14th century

1 a : the apparent junction of earth and sky b : the great circle on the celestial sphere formed by the intersection of the celestial sphere with a plane tangent to the earth's surface at an observer's position — see azimuth illustration c : range of perception or experience d : something that might be attained <new horizons>
2 a : the geological deposit of a particular time usually identified by distinctive fossils b : any of the reasonably distinct layers of soil or its underlying material in a vertical section of land c : a cultural area or level of development indicated by separated groups of artifacts

— ho·ri·zon·al \-ˈrī-z^ən-əl\ adjective