Webster's Revised Unabridged Dictionary · 1913

Deflection

Deflection , noun

[Latin deflexio, from deflectere: compare French déflexion.]

1.
The act of turning aside, or state of being turned aside; a turning from a right line or proper course; a bending, esp. downward; deviation.
The other leads to the same point, through certain deflections. — Lowth
2.
(Gunnery) The deviation of a shot or ball from its true course.
3.
(Optics) A deviation of the rays of light toward the surface of an opaque body; inflection; diffraction.
4.
(Engineering) The bending which a beam or girder undergoes from its own weight or by reason of a load.