Eiffel Tower's composition
I believe the answer is:
iron
'eiffel tower's composition' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for iron that I've seen before include "Metal (that may be pumped?)" , "medicinal preparation for the anaemic?" , "Revolver" , "Club; element" , "See 14" .)