System of raised writing (7)
I believe the answer is:
braille
'system of raised writing' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for braille that I've seen before include "Written language for the visually impaired" , "Writing system for the blind" , "Uneven writing" , "Liberal language for blind people" , "System of writing for the visually-impaired" .)