■ noun
1》 the rear surface of the human body from the shoulders to the hips.
↘the corresponding upper surface of an animal's body.
↘the spine.
↘the main structure of a ship's hull or an aircraft's fuselage.
2》 the side or part of something away from the spectator or from the direction in which it moves or faces.
↘the side or part of an object opposed to the one that is normally seen or used.
↘the part of a chair against which the sitter's ~ rests.
3》 a player in a team game who plays in a defensive position behind the forwards.
■ adverb
1》 in the opposite direction from the one that one is facing or travelling towards.
↘at a distance away.
↘(also ~ of ) N. Amer. informal behind.
2》 so as to return to an earlier or normal position or condition.
3》 in or into the past.
4》 in return.
■ verb
1》 give material or moral support to.
↘bet money on (a person or animal) winning a race or contest.
2》 cover the ~ of (something) for support, protection, or decoration.
3》 (especially in popular music) provide musical accompaniment to (a singer or musician).
4》 walk or drive ~wards.
↘(of the wind) change direction anticlockwise around the points of the compass. The opposite of veer 1 .
5》 ( ~ on/on to ) (of a building or other structure) have its ~ facing or adjacent to.
↘lie behind.
■ adjective
1》 of or at the ~.
2》 in a remote or subsidiary position.
3》 from or relating to the past: ~ pay.
4》 directed towards the rear or in a reversed course.
5》 Phonetics (of a sound) articulated at the ~ of the mouth.
Phrases
at someone's ~ in pursuit or support of someone.
~ and forth to and fro.
~ in the day in the past.
the ~ of beyond a very remote or inaccessible place.
~ to front Brit. with the ~ at the front and the front at the ~.
~ water reverse the action of the oars to slow down or stop a boat.
behind someone's ~ without a person's knowledge and in an unfair way.
get (or put ) someone's ~ up annoy or anger someone.
put one's ~ into approach (a task) with vigour.
turn one's ~ on ignore; reject.
with one's ~ to (or up against ) the wall in a desperate situation.
Phrasal verbs
~ down concede defeat.
~ off draw ~ from action or confrontation.
~ out withdraw from a commitment.
~ up (of vehicles) form into a queue due to congestion.
~ something up Computing make a spare copy of (data or a disk).
Derivatives
~er noun
~less adjective
~most adjective
Origin
OE bæc , of Gmc origin.