I
adj., adv.
1) back to (things are back to normal)
2) way back (way back in the eighteenth century)
3) (misc.) to go back on one's promise/word ('to fail to keep one's promise')
II
n.
part of the body opposite to the front
1) to turn one's back to smb.; (usu. fig.) to turn one's back on smb.
2) to arch one's back (the cat arched its back)
3) a broad back
4) on one's, smb.'s back (to lie on one's back; a heavy bag was on his back)
5) to stand back to back; they stood with their backs to the door
rear part
6) at, in the back (of) (a room at the back of the house; we sat in the back of the car)
7) from the back
area behind smt.
8) at the, in (AE) back of (BE: a garden at the back of the house = AE: a yard in back of the house)
misc.
9) he did it behind my back ('he did it without my knowledge'); in the back of one's mind ('subconsciously'); to break one's back ('to work very hard'); to get one's back up ('to balk at smt.'); get off my back (colloq.) ('leave me alone'); if you scratch my back, I'll scratch yours (colloq.) ('if you help me, I'll help you'); in back of (AE) ('behind'); to have one's back to the wall ('to be in a desperate position'); to break the back of a job ('to do most of a job'); to put some back into one's work ('to make a maximum physical effort'); who will sit in back.
III
v.
1) (D; tr.) ('to support') to back against (the independents will back us against the majority party)
2) (D; tr.) to back for (we will back her for public office)
3) (d; intr., tr.) ('to move') to back into (to back into a garage; she backed the car into the driveway)
4) (d; intr., tr.) to back out of (he backed out of the driveway; to back a car out of a garage)
5) (D; intr.) ('to withdraw') to back out of (they backed out of the deal)