Saudade /so-DAH-jee/ -- nostalgia, longing, homesickness, Fernweh, regret. It's the flavor of most Brazilian music, obviously saturating bossa nova but detectable even in more festive styles, much as the blues are tinged with hard times whether or not they put a grin on your face.
For unbloggable reasons I'm feeling that saudade more acutely now. I can't stop listening to the stuff and can barely stand it when I do.