Where earth meets sky (7)
I believe the answer is:
horizon
'where earth meets sky' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for horizon that I've seen before include "The line at which the sky and the earth appear to meet" , "Where the sky appears to meet the earth" , "Line where sky meets sea" , "As far as the eye can see" , "As far as one can see" .)