Definition of roach

• n. - A cockroach.
• n. - A European fresh-water fish of the Carp family (Leuciscus rutilus). It is silver-white, with a greenish back.
• n. - An American chub (Semotilus bullaris); the fallfish.
• n. - The redfin, or shiner.
• n. - A convex curve or arch cut in the edge of a sail to prevent chafing, or to secure a better fit.
• v. t. - To cause to arch.
• v. t. - To cut off, as a horse's mane, so that the part left shall stand upright.