Line, say, reflected poem as written (8)
I believe the answer is:
geodesic
'line say reflected poem as written' is the definition.
I can't judge whether this definition defines the answer.
'say reflected poem as written' is the wordplay.
'say' becomes 'eg' (both can mean for example).
'reflected' is a reversal indicator (letters reflected back).
'poem' becomes 'ode' (ode is a type of poem).
'as written' becomes 'sic' (I've seen this in another clue).
'eg' back-to-front is 'ge'.
'ge'+'ode'+'sic'='GEODESIC'
Can you help me to learn more?
(Other definitions for geodesic that I've seen before include "(Of dome) made up of triangles and polygons" , "Like a type of dome" , "shortest way from A to B" .)