perpetual : Idioms & Phrases

• at any given place, the boundary of that space around the elevated pole, within which the stars never set. Its distance from the pole is equal to the latitude of the place.

Webster 1913

• . See under Circle.

Webster 1913

• at any given place, the boundary of the space around the depressed pole, within which the stars never rise.

Webster 1913

• a screw used to give motion to a toothed wheel by the action of its threads between the teeth of the wheel; called also a worm.

Webster 1913

• noun a chart or mechanical device that indicates the days of the week corresponding to any given date over a long period of years
  

WordNet

• a calendar so devised that it may be adjusted for any month or year.

Webster 1913

• (Ch. of Eng.), a curacy in which all the tithes are appropriated, and no vicarage is endowed. Blackstone.

Webster 1913

• noun motion that continues indefinitely without any external source of energy; impossible in practice because of friction
  

WordNet

• . See under Motion.

Webster 1913

• noun a machine that can continue to do work indefinitely without drawing energy from some external source; impossible under the law of conservation of energy
  

WordNet

• . See Endless screw, under Screw.

Webster 1913

• noun a warrant with no expiration date
  

WordNet