| rodent ulcer | An obsolete term for a slowly enlarging ulcerated basal cell carcinoma, usually on the face. (05 Mar 2000) |
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| rodentia | <zoology> An order of mammals having two (rarely four) large incisor teeth in each jaw, distant from the molar teeth. The rats, squirrels, rabbits, marmots, and beavers belong to this order. The incisor teeth are long, curved, and strongly enameled on the outside, so as to keep a cutting edge. They have a persistent pulp and grow continuously. Origin: NL. See Rodent. Source: Websters Dictionary (01 Mar 1998) |
| rodenticide | <chemistry> Any chemical used to kill rodents (rats, mice, etc.) (17 Dec 1997) |
| rodenticides | Substances used to destroy or inhibit the action of rats, mice, or other rodents. (12 Dec 1998) |
| rodge | <zoology> The gadwall. Source: Websters Dictionary (01 Mar 1998) |
| rodomontade | Vain boasting; empty bluster or vaunting; rant. "I could show that the rodomontades of Almanzor are neither so irrational nor impossible." (Dryden) Origin: F, fr. It. Rodomontana. See Rodomont. Source: Websters Dictionary (01 Mar 1998) |
| rodonalgia | Synonym: erythromelalgia. Origin: G. Rhodon, rose, + algos, pain (05 Mar 2000) |
| rods (retina) | One of the two photoreceptor cell types of the vertebrate retina. In rods the photopigment is in stacks of membranous disks separate from the outer cell membrane. Rods are more sensitive to light than cones, but rod mediated vision has less spatial and temporal resolution than cone vision. (12 Dec 1998) |