Inventor turned side-on (6)
I believe the answer is:
edison
'inventor' is the definition.
(I know that Edison is or was a inventor)
'turned side-on' is the wordplay.
'turned' says the letters should be written in reverse.
'side' backwards is 'edis'.
'edis'+'on'='EDISON'
(Other definitions for edison that I've seen before include "Inventor of the light bulb" , "No side to this american inventor" , "Science master" , "Thomas ......, famous American inventor" , "Incandescent light inventor" .)