Dial

Dial refers to a circular or curved face on a device that displays information or sets a parameter. Clocks and watches use dials with numbers and markers and hands to indicate time. Gauges and meters use dials to show values such as speed, pressure, or temperature. A dial may also describe the interface surface on dashboards or instrument panels, where a hand or pointer shows a reading.

Control dial: A dial is also a rotary control—a knob or wheel with a marked scale rotated to adjust a setting. Dials are common for volume, tuning, brightness, or calibration, and may include detents, a pointer window, or a non-linear scale.

Telephony and dialing: In telephony, dial historically referred to turning a rotary dial to place a call; rotary dial phones used pulse dialing. Today dialing is typically done by keypad or touchscreen. The verb “to dial” can mean to enter a number on a phone, and the phrasal verb “dial in” means to calibrate or fine-tune a setting or to participate remotely in a conference or activity.

Other uses: The term appears in specialized equipment as dial indicator, a precision instrument with a dial face and a pointer used to measure small motions; and as a dial plate on a control panel. The concept of a dial crosses engineering, instrumentation, and consumer electronics, encompassing both display faces and adjustable controls.