[waves] (7)
'waves' is the definition.
(to billow is to wave or swell)
This is all the clue.
(Other definitions for billows that I've seen before include "Great waves" , "Swells" , "Big waves" .)
'waves' is the definition.
(roller is a kind of wave)
This is the entire clue.
(Other definitions for rollers that I've seen before include "expensive cars" , "They may be used to paint" , "Long heavy sea waves" .)
(Other definitions for radio that I've seen before include "Broadcaster" , "MW, LW or FM sound source" , "Electronic medium of communication" , "Communications receiver" , "Communications medium" .)