Volume of maps (5)
I believe the answer is:
atlas
'volume of maps' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for atlas that I've seen before include "Segment of spine" , "Titan compelled by Zeus to support the sky" , "He had the world on his shoulders" , "I carry a huge weight" , "Mythological Titan (involved with the world of maps?)" .)