Seems kind of IMHOish – sending this one over there. (And the OP is correct – 12 is way more than “several”).
Hal Briston – MPSIMS Moderator
I would never think of several meaning three. I see the word as being used for a low, not immediately countable number. So at least five. Many is a higher number that would take more than a couple of seconds to count. As 12 is not many, I see no problem calling it several.
Anything below five, and I see no reason no reason not to just say the number (using “couple” for two). Few is used for an indeterminate amount under 7 or so.
Of course, all of this depends on context and expectations. I’m just thinking in general terms.
Again, the numbers are not different. Using the word ‘few’ tends to diminish the importance, ‘several’ tends to amplify the importance.
Wait, are you, Melchior, actually being descriptivist here? 
‘Prescriptivism’ is descriptivism derived from those with good taste. It’s all about refinement and discernment.
I think several derives from the word sever, what you get when you cut something up - several pieces.
Context, context, context.
“Several days” might be 3-6. But mainly when talking about immediate events. In a discussion about a very long period of time, the upper limit could be much higher.
Saying “Several languages have property X.” might be referring to dozens or even hundreds of languages.
It could be a relative number. “Several meteorites have been found that are made of iron-nickel alloy.” I.e., they make up a small percentage of something. So those might number in the thousands.
So it can also apply to really large numbers. “Several stars rotate very fast.” So there might be an innumerable number of such stars.
See, that’s why I’m disagreeing about the context angle. I would never think “several meteorites” means “thousands,” no matter the scale. Never ever. If it were thousands, it would be presented as “several thousand meteorites,” not simply “several.”
That’s why I’m arguing with the context angle. It seems, on the face, that it should make sense, but I can’t think of an actual case in speech where several would refer to a number that large.
I agree with Dallas Jones but I would add in “a whole lot” between “a lot” and a “buttload”.
I learned these as a child asking for cookies…
“I said you could have ONE! What part of ONE was confusing?”
“Yeah, you can have a couple.”
“You may take three, but only because I’m in a good mood.”
“Just take a few.” (4 or 5 – the |f| was the clue)
“Give me several” (Sev =@ 7)
“I’ll take a bunch” (8 - 10)
About a dozen (9 - 11)
A dozen (12)
A half-dozen (6)
A whole bunch (13+ and nobody ever asked for a half-bunch)
Lots, a whole lot, tons = ??? close to 20 or more
—G!
So, how many licks DOES it take to get to the center of a Tootsie-Pop?
For me, several is 3. 4 is few and 2 is couple. Few for me is like 4-10. After that it’s many.
Actually, that would be “the OP’s WIFE is correct”; I had been fine with 12 being several 
Interesting replies! I didn’t think my little question would get to a second page of posts.
I’m glad most agree it’s more than 3- I could not accept 3 being several. The upper bound I have less problem with- now and forever after I will think of ‘several’ in general terms as being between 4 and 7ish, but possibly more depending on context.
Whether it’s “several,” “a few” or “a couple,” I’ve noticed Thai subtitles in films and on TV always, and I mean always, translate it as “2-3.”
Exactly 7.
Interesting to see so many people here equating “several” with “seven.” I mean, I see why that is, but it’s not a connection I was ever taught or noted in conversation (and there is no relation between the words.)
For Thais, it seems to be what they’re hearing. Syllables don’t end in the R or L sound for them, not to mention there’s no V sound in Thai, so it’s a difficult word for them on the best of days. But they really think you are literally saying “seven.”
More than a few, less than a plethora.
I have never heard of “several” being less than “few” before.
“Several” to me has always been four or more, with no specific upper limit, but I would use “less than a dozen” starting at ten.
To add: That’s in general conversation. Again, in subtitles it’s always translated as “2-3,” just like that.