ABERRATION n.
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 chromat…
ALTERNATE a.
es, singly at different heights of the stem, and at equal intervals as respects angular divergence. Gray. Alternate alligation. See Alligation. -- Alternate angles (Geom.), the internal and angles made by two lines with a third, on opposite sides of it. It the parallels AB, CD, are cut by the line EF, the angles AGH,…