- roseA shrub of the genus Rosa, with red, pink, white or yellow flowers.
- rhodiumA rare, hard, silvery-white, inert metallic chemical element (symbol Rh) with an atomic number of 45.
- rhodopsinA light-sensitive pigment in the rod cells of the retina; it consists of an opsin protein bound to the carotenoid retinal
- rhodoniteA manganese inosilicate mineral with some substitution by iron and magnesium, of composition (Mn²⁺,Fe,Mg,Ca)SiO₃.
- rhodococcusAny bacterium of the genus Rhodococcus.
- lignum rhodiumThe fragrant wood of several shrubs and trees, especially of species Convolvulus scoparius and Convolvulus floridus (Convolvulaceae) from the Canary Islands, and of the West Indian Amyris balsamifera (Rutaceae).
- rhodo-rose-colored
- rhodomelA form of mead made with rosehips, rose petals, or rose attar.
- RhodostauroticRosicrucian
- sub rosaCovertly or in secret; confidentially, privately, secretly.