Kind of line, say, elevated poems, I see (8)
I believe the answer is:
geodesic
'kind of line' is the definition.
(I know that geodesic is a type of line)
'say elevated poems i see' is the wordplay.
'say' becomes 'eg' (both can mean for example).
'elevated' says the letters should be written in reverse (in a down clue, letters go up).
'poems' becomes 'odes' (ode is a kind of poem).
'see' becomes 'C' (the word for the letter, according to Chambers).
'eg' reversed gives 'ge'.
'ge'+'odes'+'i'+'c'='GEODESIC'
(Other definitions for geodesic that I've seen before include "Like a type of dome" , "shortest way from A to B" , "(Of dome) made up of triangles and polygons" .)