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As others have said bokeh is background blur. (?, I may be wrong here, who knows)
Nope, bokeh is not background blur, it's the quality of the blur. You can take the same subject at the same aperture with two lenses of the same focal length where one will have good (creamy) bokeh and the other will have busy, ugly bokeh.
Lots of things factor in: the shape of the aperture, the lens design, etc. Few blades like 5 or so, tend to create less pleasing bokeh. That's one reason Leica rangefinder lenses, such as Summicrons, look great. They don't have to stop down and open up on every exposure, so they use a ton of blades to make an aperture that's an almost perfect circle. Old, symmetrical lens designs usually render nice bokeh. Very simple designs, like the LensBaby single element lens, have nice bokeh (but a lot of other problems that are their selling point).