Plain English Meaning
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.
Full 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.
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.