Pole from a standard pack (4)
I believe the answer is:
mast
'pole' is the definition.
(I know that mast is a type of spar)
'from a standard pack' is the wordplay.
'pack' says the answer is hidden in the clue (I've seen 'packing' mean this).
'MAST' is hidden in the letters of 'from a standard'.
(Other definitions for mast that I've seen before include "Pole aboard; fruit for pigs" , "Tall radio transmitter" , "Nuts for pigs" , "Upright transmitter; fruit of oak trees" , "Pole on ship" .)