Feature one runs occasionally (4)
I believe the answer is:
nose
'feature' is the definition.
(I know that nose is a type of science)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for nose that I've seen before include "Facial part" , "In-your-face" , "Conk (slang)" , "Nuzzle" , "Hooter" .)