| Rosh Hashanah |
the beginning of the New Year according to the lunar Jewish calendar, celebrated as a high holy day on the first day or first and second days of Tishri. |
| Rosicrucian |
a member of a seventeenth- and eighteenth-century secret society that professed esoteric religious principles and possession of occult knowledge and powers. [3 definitions] |
| rosin |
a translucent, yellow-brown, brittle residue of the distillation of turpentine from pine sap, used as a friction-increasing agent, as on the bows of certain stringed instruments, and in manufacturing varnish, inks, and soap. [3 definitions] |
| rosin oil |
a viscous, brownish, odorless oil obtained by fractional distillation of rosin and used in lubricants, electrical insulation, and inks. |
| rosinweed |
any of several related, composite, North American plants that have a resinous sap, sticky exterior, and strong aroma, such as the compass plant or the gum plant. |
| roster |
a list of names of individuals or groups belonging to or participating in an organization, class, military or police unit, or the like. [2 definitions] |
| rostrum |
a raised platform or dais for public speaking. |
| rosy |
deep reddish pink. [4 definitions] |
| rosy finch |
any of several related finches, found in western North America and eastern Asia, that have rose-colored tinting on the wings, rump, tail, or the like. |
| rot |
to decompose or decay, as organic matter. [12 definitions] |
| rotameter |
an instrument that measures the rate of flow of a liquid by means of a movable float encased in a vertical tube. |
| rotary |
turning or able to turn on an axis; rotating. [4 definitions] |
| Rotary Club |
a local unit of an international men's service organization. |
| rotary engine |
an engine in which rotation is produced by supplying power directly to the rotary parts, such as a turbine. [2 definitions] |
| rotary press |
a printing press with the type mounted on plates on a rotating cylinder, fed by a continuous roll of paper. |
| rotary-wing aircraft |
an aircraft such as a helicopter that is supported by an airfoil that rotates around a vertical axis. |
| rotate |
to cause to revolve around an axis. [5 definitions] |
| rotation |
the action of turning on or around an axis. [5 definitions] |
| rotation of crops |
a system planting different crops in a fixed, repeated order in the same field so that each successive crop restores soil nutrients that were absorbed by the previous one. |
| rotative |
of or characterized by rotation; rotating. [2 definitions] |
| rotator |
one that rotates. [2 definitions] |