This really bothers me. I feel like the only person who doesn’t know what those letters stand for. EP and LP… I DON’T KNOW!!! help… me…
EP - 6 hours
LP - 4 hours
SP - 2 hours
If you’re speaking of vinyl records:
EP - Extra Play. Usually a single with a couple extra songs thrown in. Hence, the “extra”
LP - Long Play. A full-length album.
Actually I think the OP is referring to Long Playing records (12"). EP’s are usually 4 songs but I must confess I don’t know what the “E” is for on that one!
D’oh! Thanks Deitro!
no.
not all tapes are equal in length.
That was quick. Thank you. So, its like when you record something on your VCR. You choose from EP LP and SP. Thank you thank you thank you.
It’s not the length of your tape but the motion of your capstan. 
NO!!! It’s like Dietrologia said!
Vinyl
If you’re talking about records, EPs meant “extended play.” There were two songs on each side, as opposed to singles. The format never really caught on in the U.S., though it did have its day in the U.K.
LP was short for “long play,” the standard record album. They were so called because the previous technology – 78 RPM disks – could only hold a few minutes of music on a side. Long play disks (33 1/3 RPM) could hold an entire movement of a symphony.
Videotape
EP is for Extended Play, SP is for Standard Play, and LP is for long play (in between). The terms are different on different players. SP is used to tape movies, since it has the highest quality (the faster the tape moves across the heads, the better the quality). EP (on mine, it’s SLP) is used to record shows off the air, since you get more onto a tape.
Thanks, RC. I was afraid I was gonna have to come in here and knock heads. “Extended Play” it is.
If you bought the Beatles’ MAGICAL MYSTERY TOUR in England in late 1967, you’d be buying an EP. Capitol Records bulked it up to LP length (by throwing on all those singles) for the U.S. release.
Magical Mystery Tour was a double EP; who can figure? That’s why it was so easy to turn it into an LP for US release.
Anyway, Jesus, I feel old. What’s an LP? :: shakes head and mutters ::
Even better, Myron, Public Image Ltd.'s Metal Box was issued in the UK as 3 12" EPs (45 rpm) in a film canister, making them nearly impossible to remove without flipping it over and shaking them out. Needless to say, record buyers in the U.S. are less enamored of clever-clever marketing, so the album was named Second Edition and issued as a single LP.
EP’s were usually 12" singles with extra (usually extended) mixes, or extra tracks, so although the E for extended originally meant, in essence, “longer than a single.” In practice, however, since the EPs were the size of an LP, EP came to mean “shorter than an album.” Nowadays there’s rarely anything extended about an EP at all; they’re just truncated albums.
Naw, “Extended Play” records were usually 7" records, spinning at 45 or 33rpm. In fact the correct phrase for a 12" single is -uh- “12” single". Let’s have no more on this.
Further to the comments about Metal Box (mine’s corroding, anyone else have this problem?) there was a rash of weird vinyl output in the late 70s early 80s, as New Wave bands pushed the envelope and…er, lost it there a moment. Anyway, what this is getting round to, is that I still have a copy of the laser-etched Split Enz album. Somewhere. Never liked ‘em, couldn’t resist a gimmick tho’.
Can’t see that happening wth MP3s can you?
hmph…
I can’t imagine where you’re getting this. I worked in a record store in a big U.S. city from 1982 to 1988, the heydey of the EP. And yes, some of them came on 7" discs, but the overwhelming majority were 12". Now a lot of the import singles I collected had extra tracks on 7" discs, so the ratio of 7" EPs to 12" EPs may have been different in say England and Japan, where most of my imports were from, but in the US, at least 80% to 90% were on 12". Now that I think of it, though, they were called 12"s almost exclusively by our club DJ customers, but EPs by almost everyone else.
Maybe it was a local thing (Chicago).
Alright, I see we’re at cross purposes here. I would have said the “heyday” of the EP was the late 50s - 60s:
I never considered the 12" single to be an “EP” really. Dunno why, perhaps because they weren’t anything like the EPs I remember my mother having. 
. . . I had not idea there were EPs around in the 50s and 60s. Were they referred to as EPs? What country? What artists? Do you have any?
Just curious. I grew up in the 70s with 7" 45s, and never saw an EP until the golden age of the dance single in the early 80s; I guess I saw those as descendents of the earlier 7" 45s. As the remix was born and grew longer and longer, the 7" no longer sufficed, and the EP was born. That’s how I understood the chronology. Interesting to hear otherwise.
Actually, vinyl is alive and well in the underground punk & indie rock scenes, mostly because it’s cheaper to get the records pressed in small quanities than on CDs, and they sound better.
In current terminology, the terms “single” and “ep” generally fallen by the wayside in favor of the generic ’ 7" ', sometimes modified by the numer of songs. this rule isn’t set in stone or anything.
LP is still used for a vinyl album. When bands release an album in both LP and CD formats, it is referred to simply as the “album.” cool thing is, unlike the major labels, indie bands actually tend to include bonus tracks on the LP rather than the CD version, which is where you generally hear people making a distinction.
One more thing:
If a band releases an album on vinyl only, it can be reffered to as EITHER the LP or the album. If it releases something on CD only, the thing is never called the “album,” but simply the CD. This reflects the general disdain that most hipper folk hold for the digital format, as they refuse to grant the “respect” implied in the term “album” to something that is released on a corporate media format, eg, the Backstreet Boys dont have any albums, but they have 5 CDs.
Hope that makes sense.
Oh yeah… the average underground rock n’ roll LP still costs only eight to ten bucks, even though the manufacturing costs are something like 3 times that of you average major label CD, which retails around 16 dollars. Which shoots the majors’ justification for the high price of music right to hell.
Oh, I see what the argument is…
In my experience, where the 7" is the primary format for the band who are self-releasing stuff paid for with lawnmowing/dope selling money, the distinction isn’t made between a 7" single and a 7" EP. most of the time, they’re just referred to as 7". when the distinction is made, it’s usually among record collectors, eg:
“I just paid 10 bucks for the Snare & the Idiots ‘Zero Worship’ EP,” quoth the collector.
“That’s stupid. Why would anyone pay ten bucks for a seven-inch?” quoth the non-collector.
“Because only 100 are known to exist, and I can get 75 for it on eBay,” the collector replies.
On the 12" side, though, you have 12" singles, 12" EPs, and LPs. singles are usually 2-3 songs, and EPs usually count as anywhere between 3 and seven. both are usually at 45 rpm.
You can fit around 13 minutes on a 33rpm 7" disc, which is mighty useful for a band that’s looking for something cheaper and more personal than a CD, but not as tacky as a cassette. You can put out five hundred 7" for around five hundred bucks. The same number of CDs will cost you about eight hundred dollars.
vinyl is better anyway… you can put a bigger picture of yourself on the cover.