Definition
The horizon is the line where the sky appears to meet the Earth or sea. It's always at eye level, no matter how high you climb. This 'line' isn't a real thing but an effect of perspective and the curvature of the Earth. It represents the limit of what you can see from a particular viewpoint. Obstacles can obscure the horizon, like mountains or buildings. Figuratively, the horizon represents the limit of your knowledge or possibilities. It's where the known meets the unknown.