>>1960697A BSO is an ultra cheap bike that's made to look appealing to people who don't anything about bikes at the expense of being a good bike to ride. Pic related is the classic example - this would still be a crappy bike if it had a rigid frame and fork, but it would be better to ride, more versatile, and almost certainly have a longer service life and even be reparable instead of disposable. But it's easier to sell a "full suspension" bike to someone who doesn't know better, so that's what goes on the rack at Walmart.