1) having guts or balls
2)the "behind the scenes"
guy(s) of an outfit or group who do a signficant contribution to
something but don't get as much recognition. Second only to the heart and
soul.
1) You've got to grow a backbone if you don't want to become
the one who gets trampled over in the end.
2) If she's the heart and
soul of the group, then those
two are the backbone of it.