What is the difference between gapless and crossfade playback?

There seems to be some confusion regarding the meaning of gapless and crossfade playback. 

Gapless or seamless playback is the uninterrupted playback of consecutive audio tracks, such that relative time distances in the original audio source are preserved over track boundaries on playback. This means that tracks will flow into the next song without pause.

Gapless is available only when playing back albums that are recorded gapless, and as a result, most if not all playlists will not be gapless.

With the most recent Prisma firmware update, gapless is now available when streaming from embedded Tidal or Qobuz in the Prisma application, as it has been for some time when playing from a network connected  hard drive or NAS.

One good example of gapless and not gapless is The Beatles "Abbey Road," where over the first side there are gaps between the songs or tracks, meaning not gapless. However on the second side there is a sequence of songs usually referred to as "the medley" that is gapless. The sequence begins with "You Never Give Me Your Money," then continues with "Sun King," "Mean Mr. Mustard," "Polythene Pam," "She Came in Through the Bathroom Window," "Golden Slumbers," "Carry That Weight" and "The End."

Additionally, Pink Floyd's "Wish You Were Here" and "The Wall", The Who's "Quadrophenia," and The Cowboy Junkies’ "The Trinity Sessions" are all gapless.

For classical, Georg Solti’s first complete stereo recordings of Wagner’s Ring Cycle, Der Ring des Nibelungen, with Wiener Philharmonic, comes immediately to mind providing over fourteen hours of gapless high opera playback.

A newer recording, and a favourite of ours here at Primare is Floating Points "Promises" with London Symphony Orchestra, and Pharoah Sanders.

For dance oriented gapless recordings, John Darko published a video recommending his top 10 techno tracks that is worth checking out, with most if not all to be found on TIDAL and Qobuz, at this link: https://youtu.be/JVYtpSRb-_Q?si=_Q0zGDWLJiqM76Es

And finally, for live albums, there are simply too many to mention, although the Variety article at the link below will provide fifty of what the authors feel are the best from which you can choose, many of which will in fact be gapless (but not necessarily all): https://variety.com/lists/best-live-albums-all-time-concerts/

Crossfade is fairly similar to gapless: it fades one track into the next. Usually, crossfade is something the end user can set in their playback software so that no silence is heard between songs, which allows for something similar to gapless playback for playlists. Crossfade is not available within the Prisma application, but can be found in most native music streaming applications that then can be cast using either AirPlay or Chromecast.