rhytidomeThe dead layers of plant bark (undergoing or having undergone secondary growth) external to that of the last formed periderm http://i.word.com/idictionary/rhytidome.
rhytidoplastyPlastic surgery to reduce the visible signs of aging in the face by removing wrinkles.
rhytidosteidAny extinct temnospondyl in the family Rhytidosteidae.
rhytinaSynonym of Steller's sea cow (Hydrodamalis gigas), a large herbivorous marine mammal.
rhytonA container from which fluids are intended to be drunk, having one handle and usually a base in the form of a head.
RHZEA tuberculosis treatment regimen consisting of rifampicin (R), isoniazid (H), pyrazinamide (Z), and ethambutol (E).
rirex imperator (“king-emperor”) or regina imperatrix (“queen-empress”); the initials by which a British monarch signed documents after his or her name from 1877 until 1947.
riaA narrow inlet of the sea formed by a flooded unglaciated river valley.
ribauldequinAn engine of war used in the Middle Ages, consisting of a protected elevated staging on wheels, and armed in front with pikes. After the 14th century it was furnished with small cannon.
ribavirinA synthetic analog of guanosine with chemical formula C₈H₁₂N₄O₅ that inhibits viral nucleic acid synthesis and is used as a broad-spectrum antiviral drug especially in the treatment of respiratory syncytial virus infection and chronic hepatitis C.
ribbandA long, narrow strip of timber bent and bolted longitudinally to the ribs of a vessel, to hold them in position and give rigidity to the framework.
ribbitrabbitRibbitrabbit is the fictional pairing, or ship (relationship), of Jax the Rabbit and Ribbit the frog from The Amazing Digital Circus on Youtube and Netflix.
RibbleA river in North Yorkshire and Lancashire, England, which flows into the Irish Sea.
RibbleheadA moorland location with a railway station and viaduct in Ingleton parish, North Yorkshire, England, previously in Craven district (OS grid ref SD7779).
RibblesdaleThe dale or upper valley of the River Ribble in North Yorkshire, England (OS grid refs SD85, SD86, SD87).
RibbletonAn eastern suburb and ward in the City of Preston, Lancashire, England (OS grid ref SD5630).
ribbonA long, narrow strip of material used for decoration of clothing or the hair or gift wrapping.
ribbonbackA decorative chairback made with slender rails of wood.
RibbonismA 19th-century popular movement of Catholics in Ireland, active against landlords and their agents, and opposed to the ideology of the Protestant Orange Order.
riboflavinYellow or orange-yellow water-soluble compound, a member of the vitamin B complex, that acts as a growth-promoting factor in humans and other animals.