oblate (noun): the first component is from Latin ob- “against, toward,” from the Indo-European root epi or opi- “against, near, at.” The second component is from Latin latus “carried,” from the Indo-European root telə- “to lift, support, weigh.” In mathematics the poles of an oblate spheroid are “carried toward” the center a sphere, making the resulting ellipsoid shorter in one dimension than in the other two. An oblate spheroid results from rotating an ellipse about its shorter axis. The earth approximates an oblate spheroid: the diameter through the poles is shorter than a diameter in the plane of the Equator. Contrast prolate; compare oblong. [53, 224]

oblique (adjective): the first component is Latin ob- “against, toward,” from the Indo-European root epi or opi- “against, near, at.” The second component is of unknown prior origin. Latin obliquus meant “sidelong, slanting, oblique.” In trigonometry an oblique triangle is one which is either acute or obtuse, but not right (in which case the two legs would be perpendicular rather than “slanting.”) In a Cartesian coordinate system the axes are usually perpendicular, but they may be oblique. [53]

oblong (adjective): the first component is Latin ob- “against, toward,” from the Indo-European root epi or opi- “against, near, at.” The second component is Latin longus “long,” from the Indo-European root del- “long.” In mathematics an oblong rectangle is longer in one dimension than in another; in other words, any non-square rectangle is oblong.