Meaning of SIMPLE PENDULUM in English

SIMPLE PENDULUM

Physics.

a hypothetical apparatus consisting of a point mass suspended from a weightless, frictionless thread whose length is constant, the motion of the body about the string being periodic and, if the angle of deviation from the original equilibrium position is small, representing simple harmonic motion (distinguished from physical pendulum ).

Random House Webster's Unabridged English dictionary.      Полный английский словарь Вебстер - Random House .