Reach across (4)
(Other definitions for bridge that I've seen before include "Four-handed card game" , "Join" , "Game; crossing" , "Card-game" , "Hard ridge on the nose" .)
'reach across' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for span that I've seen before include "Extent of aircraft's wing" , "Ox team; bridge" , "Bridge - spick and ___" , "Length of bridge - 9 inches!" , "Go across" .)