Antonyms of linear :
cubic, digital, nonlinear, planar, three-dimensional, two-dimensional, brick-shaped, boxlike, placoid, platelike, cubical, cuboid, boxy, flat, coplanar, box-shaped, cubiform, tabular, compound, cuboidal, cubelike, cube-shaped, isometric, blocky, crosswise, blockish, planate, flattened, solid, bowed, rounded, entwined, kinked, swirled, turned, turning, twined, twining, twisted, twisting, veering, warped, bending, coiled, coiling, corkscrew, curled, curling, curved, curving, looped, looping, spiral, spiraling, wavy, winding, meandering, weaving, devious, serpentine, sinuous, crooked, zigzag, zigzagging.
Examples of usage:
The smaller fossil, having only half the linear dimensions of the other, was probably only one- twelfth of its bulk. "The Student's Elements of Geology", Sir Charles Lyell.
Other species contain linear sporidia, which are often the length of the ascus, and may either be simple or septate. "Fungi: Their Nature and Uses", Mordecai Cubitt Cooke.
Leaves: Small, linear, alternately scattered along stem, or oblong in pairs or threes on leafy sterile shoots. "Wild Flowers Worth Knowing", Neltje Blanchan et al.