onground

On ground, or on-ground, is an adjective and adverb used to describe something that is located at or in contact with the Earth’s surface. It typically denotes a state opposite to being in the air, underwater, underground, or in space. The phrase appears across disciplines and everyday language, often signaling physical contact with the ground plane or a surface-based condition.

In transportation and aviation, on-ground indicates that a vehicle or aircraft is on the surface rather than airborne. Ground operations may include fueling, maintenance, boarding, and servicing while the vehicle remains stationary or taxiing on the surface. In everyday usage, calling something on the ground emphasizes that it is not in flight or motion through the air.

In robotics, drones, and mobility systems, on-ground contact refers to sensors and states related to contact with or proximity to the ground. Detecting ground contact helps with stability, navigation, tipping prevention, and pose estimation. Designs often incorporate ground-touch sensors, bumper switches, or wheel-based contact measurements to maintain safe operation.

In computing and simulations, on-ground or ground state can refer to a character or object’s stance on a ground plane within a virtual environment. This state often governs mechanics such as jumping, landing, or friction interactions.

In electrical engineering, ground (or earth) is the reference potential for circuits. While separate from the physical notion of being on the ground, grounding is a safety and signal-reference concept that coexists with the everyday sense of ground in descriptive usage. See also ground, ground level, earth, terrestrial.