horizon

noun
1

The visible horizontal line (in all directions) where the sky appears to meet the earth in the distance.

"A tall building was visible on the whole sweep of the horizon."

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

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

4

A specific layer of soil, or stratum

5

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

6

Any level line or surface.

7

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

Source: https://en.wiktionary.org/wiki/horizon

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