horizons

noun

1. 1

   The visible horizontal line or point (in all directions) that appears to connect the Earth to the sky.

   “A tall building was visible on the horizon.”

2. 2

   The range or limit of one's knowledge, experience or interest; a boundary or threshold.

   “Some students take a gap year after finishing high school to broaden their horizons.”

3. 3

   The range or limit of any dimension in which one exists.

4. 4

   A specific layer of soil or strata

5. 5

   A cultural sub-period or level within a more encompassing time period.

6. 6

   Any level line or surface.

7. 7

   The point at which a computer chess algorithm stops searching for further moves.