aberration
n.n. a strange or unusual mistake that is not normal. In science, it can also describe a shape that causes light or sound to bend incorrectly.
n. a deviation from what is normal, expected, or acceptable. In technical contexts, it refers to a defect in a lens or mirror that causes light rays to fail to converge at a single point.
The error was a minor aberration in the data.
The scientist noted that the unusual weather pattern was a temporary aberration rather than a sign of long-term climate change.
Optical aberrations in the telescope's primary mirror caused the stars to appear as blurry disks rather than sharp points of light, necessitating a complex correction process.
A learned borrowing from Latin aberrātiō(n) (“relief, diversion”), first attested in 1594, from aberrō (“wander away, go astray”), from ab (“away”) + errō (“wander”). Compare French aberration. By surface analysis, aberrat(e) + -ion.