Note that can go either way (5)
I believe the answer is:
minim
This clue is a double definition.
'note' is the first definition.
(type of musical note)
'that can go either way' is the second definition.
(Other definitions for minim that I've seen before include "Note equal to two crochets" , "Musical note - small amount of liquid" , "Note of two crotchets" , "Beat" , "Short note" .)