n.

1. 地平線[the S]
   The sun has risen above the horizon.

   太陽已從地平線升起。

   At last, they saw an island on the horizon.

   終於他們見到地平線上有一個島。

2. （知識，經驗等的）範圍；眼界；視野[C]
   Good novels broaden your horizons.

   好小說開闊人的眼界。

n.

1. the line at which the earth's surface and the sky appear to meet.
   ▸ (also apparent horizon) this line represented as a circle, 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.
2. the limit of a person's knowledge, experience, or interest.
3. Geology  & Archaeology  a layer or level of soil or rock with particular characteristics or representing a particular period.