rod

Rod can refer to several distinct concepts in science, engineering, and culture. In everyday use, a rod is a slender, straight bar or post that serves as a structural element or support in construction, machinery, or tools. The term also appears in specialized contexts, where the exact meaning depends on the field.

As a given name, Rod is often a shortened form of Rodney or, less commonly, Rodrick. It is also used as a surname. Notable people named Rod include Rod Stewart, a British singer; Rod Laver, an Australian tennis player; Rod Serling, an American writer and creator of the Twilight Zone; and Rod Steiger, an American actor.

In biology, rod cells are one of the two principal types of photoreceptor cells in the retina. Rods are highly sensitive to light and enable vision in low-light conditions, but they do not detect color. They function together with cone cells to provide peripheral vision and motion detection, especially in dim environments.

In physics and engineering, a rod is a slender, rigid object whose length greatly exceeds its cross-sectional dimensions. It is used as a fundamental element in mechanical models and as a component in various devices, such as connecting rods in engines or measuring rods in metrology.

In radio and communications, a rod antenna, also known as a monopole, is a straight rod used as the radiating element for transmitting or receiving radio signals. Rods of various materials and lengths are chosen to suit specific frequencies and applications.