Aeronautics. the top part or upper surface of an aircraft, especially of its fuselage.
:Bookbinding. the edge of a book formed where its sections are bound together.
:the backs, grounds along the River Cam in back of certain colleges at Cambridge University in England: noted for their great beauty.
:Architecture. extrados.
:Carpentry. the upper side of a joist, rafter, handrail, etc.the area of interior wall between a window stool and the floor.
:Mining. the roof of a stope or drift.
:Sports. a player whose regular position is behind that of players who make initial contact with the opposing team, as behind the forward line in football or nearest the player's own goal in polo.the position occupied by this player.
v.有主动词 verb
1
:to support, as with authority, influence, help, or money: to back a candidate; to back up a theory with facts.
:to bet on: to back a horse in the race.
:to cause to move backward: to back a car.
:to furnish with a back: to back a book.
:to lie at the back of; form a back or background for: a beach backed by hills.
:to provide with an accompaniment: a singer backed by piano and bass.
:to get upon the back of; mount.
:to write or print on the back of; endorse; countersign.
:Carpentry. to attach strips of wood to the upper edge of to bring it to a desired level.
:Nautical. to alter the position of so that the wind will strike the forward face.to brace in backing a sail.to reinforce the hold of by means of a smaller one attached to it and dropped farther away.
v.无主动词 verb
1
:to go or move backward.
:Nautical. to change direction counterclockwise.
adj.形容词 adjective
1
:situated at or in the rear: at the back door; back fence.
:far away or removed from the front or main area, position, or rank; remote: back settlements.
:belonging to the past: back files; back issues.
:in arrears; overdue: back pay.
:coming or going back; moving backward: back current.
:Navigation. reciprocal.
:Phonetics. produced with the tongue articulating in the back part of the mouth, as in either of the sounds of go.
1
:back away, to retreat; withdraw: They gradually began to back away from their earlier opinion.
:back down, to abandon an argument, opinion, or claim; withdraw; retreat: He backed down as soon as a member of the audience challenged his assertion.
:back off, to back down: Now that the time for action had arrived, it was too late to back off.Textiles.to reverse in mule spinning prior to winding on the newly spun length of yarn.
:back out, to fail to keep an engagement or promise; withdraw from; abandon: Two entrants have backed out of competing in the marathon. You can't back out now.
:back up, to bring to a standstill: A stalled car backed up traffic for miles.Printing.to print a sheet again on its other side.Printing.to fill in with metal in order to strengthen it.to move backward: Back up into the garage.to reinforce: We backed up the cardboard with slats so it wouldn't fall down.to support or confirm: He backed up my story and they let us go.Computers.to duplicate as a precaution against failure.
:back up for, Australian Informal. to return for more of, as another helping of food.