- the line along which the sky seems to touch the earth; visible horizon
- the outline, as of a city, seen against the sky
- The line along which the surface of the earth and the sky appear to meet; the horizon.
- The outline of a group of buildings or a mountain range seen against the sky.
(third-person singular simple present skylines, present participle skylining, simple past and past participle skylined)
- To outline something against the sky.