(astronomy) A large impact crater that has a relatively flat floor, surrounded by a wall

plural of walled plain

(of a wall clock) Having an exposed pendulum.

plural of retaining wall

plural of screen wall

(climbing) An artificial wall used for the sport of climbing

(squash, racquetball) The main and largest wall in court, located at the front of the world; the wall which the ball must hit in a rally. / Used other than figuratively or idiomatically: see front, wall.

(squash, racquetball) The wall at the back of a racquetball or squash court, directly opposite the front wall. / Used other than figuratively or idiomatically: see back, wall.

(squash, racquetball) Either of the two parallel walls in a court, perpendicular to the front wall; either of the walls on the side of the court.

(idiomatic) To make an all-out effort. / (idiomatic) To fail, to run out of options. (especially of a business) / To be put aside or forgotten. / To take an extreme and determined position or measure.