1. A large amount of drugs, 5 kilos or more...typically high quality cocaine or the term can be used loosely for any white prescription pills in high quantity. Designer drugs such as ecstacy that are light in coloration...yellowish/white, have also been refered to as white swans, this statement incorrect.
2. A pure substance
Q: He's got 2 beemers, a range rover and a lexus what kinda drugs does he sell?....A: White Swans
Got any White Swans?....Who are you Tony Montana?!?!