A "listen" on Whooshkaa is an individual download of an episode hosted by Whooshkaa that has been filtered to establish that -- among other things -- enough of the episode was downloaded to constitute a real person listening. This term may be used interchangeably with “download”.
A "unique listen" is a listen that has occurred to a specific podcast episode from an identified individual through a single (UTC-based) day. For example, if the individual has performed a listen the same podcast on the same UTC-based day twice, that will result in two listens and one unique listen. If the same person listens to the same episode the following day again, it will count as 3 listens and 2 unique listens.
As of November 2019, all of the listens reported on Whooshkaa (unless otherwise stated) are unique listens.