Webster's English Dictionary

Enter the word to look up:

horizon

Cross references:
  1. apparent horizon       2. celestial horizon     
 
ho.ri.zon \h*-'ri-z-*n\ \-'ri-z-n*l, -*n-*l\ n [ME orizon, fr. LL 
   horizont-, horizon, fr. Gk horizont-], horizo-n, fr. prp. of horizein to 
   bound, define, fr. horos boundary; akin to L urvus circumference of a city 
   1a: the apparent junction of earth and sky  1b1: the plane tangent to the 
   earth's surface at an observer's position  1b2: the plane parallel to the 
   sensible horizon but passing through the ear th's center; also : the great 
   circle formed by the intersection of this plane with the celestial sphere 
   1c: a level mirror (as the surface of mercury in a shallow vessel or a plan 
   e reflector adjusted to the true level artificially) used esp. in observing 
   altitudes 1d: range of perception or experience  2a: the geological deposit 
   of a particular time usu. identified by distinct ive fossils 2b: any of the 
   reasonably distinct layers of soil or its underlying materia l in a 
   vertical section of land 2c: a cultural area or level of development 
   indicated by separated groups o f artifacts - ho.ri.zon.al aj