Guided by small light (3)
I believe the answer is:
led
I believe this clue is a double definition.
'guided' is the first definition.
(similar in meaning)
'small light' is the second definition.
(light emitting diode)
'by' is the link.
(Other definitions for led that I've seen before include "Something emitting light" , "showed the way ahead" , "Came first" , "induced to" , "Took by the hand and showed the way" .)