Interchange (4)
'interchange' is the definition.
(synonyms)
This is all the clue.
(Other definitions for alternate that I've seen before include "Happen in turns, rotate" , "Substitute" , "In turns, first one then the other" , "Take turns" , "Happening or following in turns, one after the other" .)
'interchange' is the definition.
(I know that swap is a type of interchange)
This is all the clue.
(Other definitions for swap that I've seen before include "Change over" , "Exchange, barter" , "Interchange" , "trade" , "exchanged gift" .)