Understand there's a little switch (4)
I believe the answer is:
twig
This could be a double definition.
'understand' is the first definition.
(I know that twig is a more specific form of the action the understand)
'a little switch' is the second definition.
'twig' can be an answer for 'switch' (thesaurus). I'm not sure about the 'a little' bit.
'there's' is the link.
Can you help me to learn more?
(Other definitions for twig that I've seen before include "Tiny end of branch" , "A small branch - geddit?" , "small piece in plane, say" , "Suddenly get" , "Small part of a branch - suddenly understand" .)