| roach | <zoology> A cockroach. 1. <zoology> A European fresh water fish of the Carp family (Leuciscus rutilus). It is silver-white, with a greenish back. An American chub (Semotilus bullaris); the fallfish. The redfin, or shiner. 2. A convex curve or arch cut in the edge of a sail to prevent chafing, or to secure a better fit. As sound as a roach [roach perhaps being a corruption of a F. Roche a rock], perfectly sound. Origin: OE. Rroche; cf. AS. Reohha, D. Rog, roch, G. Roche, LG. Ruche, Dan. Rokke ray, Sw. Rocka, and E. Ray a fish. Source: Websters Dictionary (01 Mar 1998) |
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| Roach clasp | A clasp whose arms are bar-type extensions from major connectors or from within the denture base; the arms pass adjacent to the soft tissues and approach the point of contact on the tooth in a gingivo-occlusal direction, a clasp consisting of two or more separate arms located opposite to each other on the tooth; the bar arms arise from the framework or from a connector and may traverse the soft tissue; one arm (bar), the retentive arm, usually terminates in the infrabulge (gingival convergence) area of the tooth; the other, the reciprocal arm, usually terminates on the suprabulge (occlusal convergence) area. Synonym: Roach clasp. (05 Mar 2000) |
| Roach, F Ewing | <person> U.S. Prosthodontist, 1868-1960. See: Roach clasp. (05 Mar 2000) |
| roach-backed | Having a back like that of roach; said of a horse whose back a convex instead of a concave curve. Source: Websters Dictionary (01 Mar 1998) |