Ăb'er-rā'tion, n.

(-rā'shun), n. [Lat. aberratio, Fr. aberration. See ABERRANCE.]

1. The act of wandering; deviation, especially from truth or moral rectitude, or from the natural state. “The aberrations of youth.” Hall. “Aberrations from theory.” Burke. Whims, which at first are the aberrations of a single brain, pass with heat into the epidemic form. I. Taylor.
2. (Astron.) A small periodical change of position in the stars and other heavenly bodies, due to the combined effect of the motion of light and the motion of the observer; called annual aberration, when the observer's motion is that of the earth in its orbit, and daily or diurnal aberration, when of the earth on its axis; amounting when greatest, in the former case, to 20″.4, and in the latter, to 0″.3. Planetary aberration is that due to the motion of light and the apparent geocentric motion of the planet.
3. (Opt.) The convergence to different foci, by a lens or mirror, of rays of light emanating from one and the same point, or the deviation of such rays from a single focus; called spherical aberration, when due to the spherical form of the lens or mirror, such form giving different foci for central and marginal rays; and chromatic aberration, when due to the different refrangibilities of the colored rays of the spectrum, those of each color having a distinct focus.
4. (Med.) A partial alienation of mind. Dunglison.
5. (Physiol.) The passage of a fluid into parts not appropriate for it. Dunglison.

Syn.—Insanity; lunacy; madness; derangement; alienation; mania; dementia. See INSANITY.