Definition
A landing gear arrangement consisting of two main wheels positioned aft of the aircraft's center of gravity and a single nosewheel forward of it, giving the aircraft a level (or near-level) attitude on the ground.
Plain English
A landing gear setup with two wheels in the middle of the aircraft and one wheel at the nose, so the airplane sits flat on the ground.
Context Anchor
Seen in taxiing, takeoff, landing, and aircraft handling discussions, especially when comparing nosewheel airplanes with tailwheel airplanes.
Derivation
From the bicycle/tricycle family of words: 'tri-' (Latin/Greek for three) plus 'cycle' (wheel). The name simply describes the three-wheel layout, but the key feature is where those wheels are placed — one at the nose, two under the wings or fuselage.
Why Pilots Care
Improves directional control and stability on the ground, reducing the risk of nose-over during braking or crosswind operations.
Intuition Check
Do not read “tricycle” as meaning the airplane works like a child’s tricycle. Here it only describes the wheel layout: nose wheel in front, main wheels behind.
Example Sentence 1
Because the Cessna 172 is a tricycle-gear aircraft, the nosewheel keeps the fuselage level during taxi and takeoff roll.
Example Sentence 2
After landing, the pilot used differential braking on the tricycle-gear trainer to make a tight turn onto the ramp.