horizon

 
Pronunciation: /həˈrʌɪz(ə)n/

noun

  • 1the line at which the earth’s surface and the sky appear to meet: the sun rose above the horizon
  • (also apparent horizon) the circular boundary of the part of the earth’s surface visible from a particular point, ignoring irregularities and obstructions.
  • (also true horizon) Astronomy a great circle of the celestial sphere, the plane of which passes through the centre of the earth and is parallel to that of the apparent horizon of a place.
  • 2 (often horizons) the limit of a person’s knowledge, experience, or interest: she wanted to leave home and broaden her horizons
  • 3 Geology a layer of soil or rock, or a set of strata, with particular characteristics.
  • Archaeology a level of an excavated site representing a particular period: the upper horizon of the site showed an arrangement of two rows of features

Phrases

on the horizon

imminent or just becoming apparent: trouble could be on the horizon

Origin:

late Middle English: via Old French from late Latin horizon, from Greek horizōn (kuklos) 'limiting (circle)'