Fit together, as gearwheel teeth (4)
I believe the answer is:
mesh
(Other definitions for mesh that I've seen before include "Interlock" , "Grid, netting" , "Netting made of wire or thread" , "harmonise" , "Entangle, entwine" .)
I believe the answer is:
mesh
(Other definitions for mesh that I've seen before include "Interlock" , "Grid, netting" , "Netting made of wire or thread" , "harmonise" , "Entangle, entwine" .)