The word "helixes" refers to a type of spiral-shaped structure, typically found in nature, such as the double helix of DNA molecules. Antonyms for "helixes" would be words that describe a completely different type of shape or structure. Some antonyms might include: straight, linear, flat, two-dimensional, planar, or even irregular. These words emphasize a lack of curvature, symmetry, or twistiness, indicating a completely contrasting shape or form. While "helixes" suggest a dynamic and complex structure, its antonyms denote a simpler, more straightforward design.