I posted about this at Piano Tell, but I thought some of you (esp @realplayer @bernard ) might know more about this, so I hope it’s ok to share my post here as well.
I’m working on “Song For Gavin” by Ludovico Einaudi right now, hoping to record it soon, and I noticed this notation:

I have Einaudi’s recording of this piece, so when I was first learning it, I didn’t think too much about the notation because I know there’s a big pause right there before the next theme. (Plus I have a bad habit of not worrying about Einaudi’s instructions in Italian because he includes them so often, and because…. because Einaudi
)
Anyway, now that I’m at the polishing stage and hoping to record this piece, I was going through the score and writing a few notes to myself and realized that not only did I not recognize the word “lunga,” I didn’t actually know what that symbol was. And it shows up four times in that measure across three beats!
So I figured I should look it up. 
Lunga is apparently Italian for “long pause,” and sometimes is written “lungo” (in Italian) or “longa” (in English). (I don’t know enough about Italian to know why Einaudi wrote the feminine here, but I assume that’s the distinction between lungo and lunga.)
I didn’t find many images that showed this symbol the way Einaudi uses it (most showed a slightly different way of writing it), but I did find this graphic:

which suggests that the lunga fits under the umbrella of fermata and presumably a different type of fermata.
I have other scores by Einaudi where he uses a fermata, so it’s clearly not the case that he uses this symbol instead of a fermata. I assume he means the lunga to be somehow different from the fermata. In terms of how to play this particular piece, I’m not worried about it (because I can hear it, in the recording and in my head). But it’s interesting to think about the subtle differences in musical symbols and wonder what the composer intends.
Also, it’s sort of surprising to me to come across an unfamiliar symbol at this stage in my piano trajectory, especially in a contemporary piece, and in music by a composer whose music I have played so much of. I wonder if anyone is asking Einaudi these kinds of questions. I certainly hope so! He’s still actively concertizing, but he will eventually retire and so on.
Anyway, have you ever seen a lunga? In classical music or contemporary?