stiff or unyielding; not pliant or flexible; hard:
a rigid strip of metal.
firmly fixed or set.
inflexible, strict, or severe:
a rigid disciplinarian; rigid rules of social behavior.
exacting; thorough; rigorous:
a rigid examination.
so as to meet precise standards; stringent:
lenses ground to rigid specifications.
Mechanics. of, relating to, or noting a body in which the distance between any pair of points remains fixed under all forces; having infinite values for its shear modulus, bulk modulus, and Young's modulus.
(of an airship or dirigible) having a form maintained by a stiff, unyielding structure contained within the envelope.
pertaining to a helicopter rotor that is held fixedly at its root.
early 15c., from Latin rigidus "hard, stiff, rough, severe," from rigere "be stiff," from PIE *reig- "stretch (tight), bind tightly, make fast" (cf. Old Irish riag "torture," Middle High German ric "band, string"). Related: Rigidly.