The penis.
A rod cell: a rod-shaped cell in the eye that is sensitive to light.
A hot rod, an automobile or other passenger motor vehicle modified to run faster and often with exterior cosmetic alterations, especially one based originally on a pre-1940s model or (currently) denoting any older vehicle thus modified.
A coupling rod or connecting rod, which links the driving wheels of a steam locomotive, and some diesel shunters and early electric locomotives.
A long slender usually tapering pole used for angling; fishing rod.
A straight, round stick, shaft, bar, cane, or staff.
A straight bar that unites moving parts of a machine, for holding parts together as a connecting rod or for transferring power as a driveshaft.
Any of a number of long, slender microorganisms.
An implement held vertically and viewed through an optical surveying instrument such as a transit, used to measure distance in land surveying and construction layout; an engineer's rod, surveyor's rod, surveying rod, leveling rod, ranging rod. The modern (US) engineer's or surveyor's rod commonly is eight or ten feet long and often designed to extend higher. In former times a surveyor's rod often was a single wooden pole or composed of multiple sectioned and socketed pieces, and besides serving as a sighting target was used to measure distance on the ground horizontally, hence for convenience was of one rod or pole in length, that is, 5+¹⁄₂ yards.
A stirring rod: a glass rod, typically about 6 inches to 1 foot long and ¹⁄₈ to ¹⁄₄ inch in diameter that can be used to stir liquids in flasks or beakers.
A stick used to measure distance, by using its established length or task-specific temporary marks along its length, or by dint of specific graduated marks.
An implement resembling and/or supplanting a rod (particularly a cane) that is used for corporal punishment, and metonymically called the rod, regardless of its actual shape and composition.
A longitudinal pole used for forming part of a framework such as an awning or tent.
A Cuisenaire rod.
A stick, pole, or bundle of switches or twigs (such as a birch), used for personal defense or to administer corporal punishment by whipping.
A pistol; a gun.
A rod-shaped object that appears in photographs or videos traveling at high speed, not seen by the person recording the event, often associated with extraterrestrial entities.
To penetrate sexually.
To reinforce concrete with metal rods.
To hot rod.
To furnish with rods, especially lightning rods.
A penis.
A short staff, a club; a cudgel.
A baton, or military staff of command, now especially the stick carried by a police officer.
To strike with a truncheon.