Catch in one trap (3)
I believe the answer is:
Here is my best explanation:
'catch' is the definition.
(netting is a kind of catching)
'in one trap' is the subsidiary indication.
'in' says the answer is hidden in the clue.
'net' is hidden within 'one trap'.
(Other definitions for net that I've seen before include "Fish trap after deductions?", "Amount remaining after deductions", "Lattice", "Mesh for the bottom line?", "Open-meshed material (used for catching things?)", "Mesh; entrap", "Capture", "What separates court opponents", "Mesh or web" and "Meshed trap".)