1. The line where the sky appears to meet the earth or sea; the apparent junction between earth/sea and sky
The sun descended below the horizon line at dusk.
O sol desceu abaixo da linha do horizonte ao anoitecer.
2. In art and perspective drawing, the horizontal line at eye level where parallel lines appear to converge
The artist carefully drew the horizon line to establish proper perspective in the landscape.
O artista desenhou cuidadosamente a linha do horizonte para estabelecer perspectiva adequada na paisagem.