Mo·tion n.
 1. The act, process, or state of changing place or position; movement; the passing of a body from one place or position to another, whether voluntary or involuntary; -- opposed to rest.
 Speaking or mute, all comeliness and grace
 attends thee, and each word, each motion, forms.   --Milton.
 2. Power of, or capacity for, motion.
    Devoid of sense and motion.   --Milton.
 3. Direction of movement; course; tendency; as, the motion of the planets is from west to east.
    In our proper motion we ascend.   --Milton.
 4. Change in the relative position of the parts of anything; action of a machine with respect to the relative movement of its parts.
    This is the great wheel to which the clock owes its motion.   --Dr. H. More.
 5. Movement of the mind, desires, or passions; mental act, or impulse to any action; internal activity.
    Let a good man obey every good motion rising in his heart, knowing that every such motion proceeds from God.   --South.
 6. A proposal or suggestion looking to action or progress; esp., a formal proposal made in a deliberative assembly; as, a motion to adjourn.
    Yes, I agree, and thank you for your motion.   --Shak.
 7. Law An application made to a court or judge orally in open court.  Its object is to obtain an order or rule directing some act to be done in favor of the applicant.
 8. Mus. Change of pitch in successive sounds, whether in the same part or in groups of parts.
    The independent motions of different parts sounding together constitute counterpoint.   --Grove.
 Note: ☞ Conjunct motion is that by single degrees of the scale. Contrary motion is that when parts move in opposite directions. Disjunct motion is motion by skips. Oblique motion is that when one part is stationary while another moves. Similar or direct motion is that when parts move in the same direction.
 9. A puppet show or puppet. [Obs.]
    What motion's this? the model of Nineveh?   --Beau. & Fl.
 Note: ☞ Motion, in mechanics, may be simple or compound. Simple motions are: (a) straight translation, which, if of indefinite duration, must be reciprocating. (b) Simple rotation, which may be either continuous or reciprocating, and when reciprocating is called oscillating. (c) Helical, which, if of indefinite duration, must be reciprocating. Compound motion consists of combinations of any of the simple motions.
 Center of motion, Harmonic motion, etc. See under Center, Harmonic, etc.
 Motion block Steam Engine, a crosshead.
 Perpetual motion Mech., an incessant motion conceived to be attainable by a machine supplying its own motive forces independently of any action from without.  According to the law of conservation of energy, such perpetual motion is impossible, and no device has yet been built that is capable of perpetual motion.
 Syn: -- See Movement.


 Per·pet·u·al a.  Neverceasing; continuing forever or for an unlimited time; unfailing; everlasting; continuous.
    Unto the kingdom of perpetual night.   --Shak.
    Perpetual feast of nectared sweets.   --Milton.
 Circle of perpetual apparition, or Circle of perpetual occultation. See under Circle.
 Perpetual calendar, a calendar so devised that it may be adjusted for any month or year.
 Perpetual curacy Ch. of Eng., a curacy in which all the tithes are appropriated, and no vicarage is endowed. --Blackstone.
 Perpetual motion. See under Motion.
 Perpetual screw. See Endless screw, under Screw.
 Syn: -- Continual; unceasing; endless; everlasting; incessant; constant; eternal. See Constant.

 ◄ ►


 perpetual motion
      n : motion that continues indefinitely without any external
          source of energy; impossible in practice because of
          friction