The visible horizontal line (in all directions) where the sky appears to meet the earth in the distance.
A specific layer of soil, or stratum
The point at which a computer chess algorithm stops searching for further moves.
Any level line or surface.
The range or limit of one's knowledge, experience or interest; a boundary or threshold.
A cultural sub-period or level within a more encompassing time period.
The range or limit of any dimension in which one exists.
The area of the atmosphere directly below the stratosphere.