What is "solid of least resistance"

Resistance \Re*sist"ance\ (-ans), n. [F. r['e]sistance, LL. resistentia, fr. resistens, -entis, p. pr. See Resist.]

1. The act of resisting; opposition, passive or active.

   When King Demetrius saw that . . . no resistance was made against him, he sent away all his forces.
   --1. Macc. xi. 38.

2. (Physics) The quality of not yielding to force or external pressure; that power of a body which acts in opposition to the impulse or pressure of another, or which prevents the effect of another power; as, the resistance of the air to a body passing through it; the resistance of a target to projectiles.

3. A means or method of resisting; that which resists.

   Unfold to us some warlike resistance.
   --Shak.

4. (Elec.) A certain hindrance or opposition to the passage of an electrical current or discharge offered by conducting bodies. It bears an inverse relation to the conductivity, -- good conductors having a small resistance, while poor conductors or insulators have a very high resistance. The unit of resistance is the ohm.

   Resistance box (Elec.), a rheostat consisting of a box or case containing a number of resistance coils of standard values so arranged that they can be combined in various ways to afford more or less resistance.

   Resistance coil (Elec.), a coil of wire introduced into an electric circuit to increase the resistance.

   Solid of least resistance (Mech.), a solid of such a form as to experience, in moving in a fluid, less resistance than any other solid having the same base, height, and volume.