1. (

• horizon ,
• apparent_horizon ,
• visible_horizon ,
• sensible_horizon ,
• skyline

) the line at which the sky and Earth appear to meet ;

2. (

• horizon ,
• view ,
• purview

) the range of interest or activity that can be anticipated; "It is beyond the horizon of present knowledge" ;

3. (

• horizon ,

) a specific layer or stratum of soil or subsoil in a vertical cross section of land ;

4. (

• horizon ,
• celestial_horizon

) the great circle on the celestial sphere whose plane passes through the sensible horizon and the center of the Earth ;