to hang down (from); to dangle; to swing; to be suspended
to be within one's reach; to dangle (before one's eyes)
to be completely reliant on; to be entirely dependent on
猿が枝にぶら下がった。
A monkey hung from a branch.
鍵がフックにぶら下がっている。
Keys are hanging from the hook.
鉄棒にぶら下がる運動は背中に良い。
Hanging from a horizontal bar is good for the back.