What is "idle wheel"

Idle \I"dle\, a. [Compar. Idler; superl. Idlest.] [OE. idel, AS. [=i]del vain, empty, useless; akin to OS. [=i]dal, D. ijdel, OHG. [=i]tal vain, empty, mere, G. eitel, Dan. & Sw. idel mere, pure, and prob. to Gr. ? clear, pure, ? to burn. Cf. Ether.]

1. Of no account; useless; vain; trifling; unprofitable; thoughtless; silly; barren. ``Deserts idle.''
   --Shak.

   Every idle word that men shall speak, they shall give account thereof in the day of judgment.
   --Matt. xii. 36.

   Down their idle weapons dropped.
   --Milton.

   This idle story became important.
   --Macaulay.

2. Not called into active service; not turned to appropriate use; unemployed; as, idle hours.

   The idle spear and shield were high uphing.
   --Milton.

3. Not employed; unoccupied with business; inactive; doing nothing; as, idle workmen.

   Why stand ye here all the day idle?
   --Matt. xx. 6.

4. Given rest and ease; averse to labor or employment; lazy; slothful; as, an idle fellow.

5. Light-headed; foolish. [Obs.]
   --Ford.

   Idle pulley (Mach.), a pulley that rests upon a belt to tighten it; a pulley that only guides a belt and is not used to transmit power.

   Idle wheel (Mach.), a gear wheel placed between two others, to transfer motion from one to the other without changing the direction of revolution.

   In idle, in vain. [Obs.] ``God saith, thou shalt not take the name of thy Lord God in idle.''
   --Chaucer.

   Syn: Unoccupied; unemployed; vacant; inactive; indolent; sluggish; slothful; useless; ineffectual; futile; frivolous; vain; trifling; unprofitable; unimportant.

   Usage: Idle, Indolent, Lazy. A propensity to inaction is expressed by each of these words; they differ in the cause and degree of this characteristic. Indolent denotes an habitual love to ease, a settled dislike of movement or effort; idle is opposed to busy, and denotes a dislike of continuous exertion. Lazy is a stronger and more contemptuous term than indolent.

n. a pulley on a shaft that presses against a guide belt to guide or tighten it [syn: idle pulley, idler pulley]