The album is an artificial construct, yet it is the main unit of organization for music. As its name suggests, it was originally a collection of separate records, in a sort of book that was similar to a photo album. (Doug Adams and I discussed the creation of the album in the very first episode of our podcast The Next Track.) For at least 70 years, the Album has dominated music sales and listening.
At the same time, the single has long been the gateway medium for discovering new artists, or for getting the latest songs by your favorite artist. This size of this record – 7 inches – was a sign of the more limited content it contained. But it also played faster, in part to fill up the record; a 7" record at 33 rpm would look half empty if it contained just one song per side. The single wasn’t only a 7" record: in Jamaica, 10" singles were common starting in the 1960s, and 12" singles started being released in the US in the early 1970s. (There were also double singles in gatefold sleeves; I recall a live set by The Cure that contained four songs on two 7" discs.)
In the 1950s and 1960s, many pop bands released multiple singles, then collected them on albums; which were similar to the original record album, which simply gathered disparate tracks. It wasn’t until the mid-1960s that the concept of the album as a continuous musical program was born (at least for pop music; classical and jazz had used albums for either entire works, or for live sets, for some time).
And in between those two, you have the EP: shorter collections of tracks, perhaps four or six, for a time released on 10" vinyl to distinguish them from their big brothers that were "full" albums. EPs became common in the UK in the 1950s, and there was even an official chart for best-selling EPs in the country from 1960 to 1967. Some bands started releasing them in the 1980s, when Epic records "created" the Nu-Disk, initially for promotional purposes, but later for general release. I specifically recall The Clash’s Black Market Clash being a 10-inch EP.
With digital music, everything has changed. When you see a bit of text on a website or in iTunes, all you know is the name of the release and its artist. David Bowie’s Let’s Dance could be a single, an EP, or an Album. This is because the tags – the metadata that identifies music – don’t allow for this type of differentiation. iTunes uses a simplified version of the ID3 tagging system, which doesn’t offer a tag to identify what type of release a record is. (MusicBrainz does use a tag called Release Group, which can be used to distinguish between singles, albums, and EPs, but also broadcasts and "other.")
So how can you distinguish between these different formats in digital? The only way is if the record label has tagged the name of a release with the word "Single" or "EP." Here’s an example of music by David Bowie:
The first release is a single, just one track, but you can’t see that because the title is truncated. The two with the cover from "Heroes" are singles, but one has three tracks and one has two. No Plan says that it is an EP, and it contains four tracks. Who Can I Be Now? is a multi-disc collection, containing 104 tracks over nine "discs" in its digital form. And Sound and Vision 2013 is a two-track single.
Some people may want to indicate in their iTunes libraries which of their "albums" are not actual albums; which are singles or EPs. There is no way you can do this visually, or at least not without some trickery: you could reduce the size of the artwork and put it on a white background so it looks smaller. But that won’t help you when you’re browsing Apple Music or another streaming service.
What could iTunes do to indicate this difference? Perhaps a small overlay icon could show the number of tracks in a release? Or there could be a bit of text – say a bullet, or an emoji – before the title of anything that isn’t a proper album. It’s not that simple, however. Would you assume that any release with, say, only two or three tracks is a single? In that case, would a single-movement symphony that lasts 45 minutes count as a single and not an album? Or would you assume that the tracks have to be shorter than, say, five or six minutes to count as a single? That would leave out Bob Dylan’s Like a Rolling Stone (6:11) and Laurie Anderson’s Oh Superman (8:21).
Any such tagging would depend on the record labels; Apple can’t scan the music and determine what the cut-off timing is for a single, an EP, or an album. Some EPs may run a half hour, and many albums are shorter than that. I think it’s unlikely that there is any solution other than text for this. And, again, this depends on the record labels tagging recordings that aren’t albums. The David Bowie recordings above are tagged correctly, but you can’t always see that last word that says "Single" or "EP."
If you want to do this for your own music library, you might want to add a character at the beginning of the album name. On the Mac, you have access to all sorts of characters:
You could, for example, use ⦿ for singles and ◉ for EPs. Or, perhaps, these two squares, the first for singles and the latter for EPs: ◻︎ ◼︎. There are all sorts of stars and other symbols you could use ☆ ✪ ✹ ✫ ❂. If you really want to mark your music like this, it’s up to you.