Fugoid

Part of speech: adjective, noun

Definitions

1. A type of motion characterized by alternating ascents and descents as seen in flying organisms
2. Describing a movement pattern in which an entity engages in a series of rise and fall cycles during travel
3. Referring to a flight or motion that includes a repetitive sequence of elevation changes, often associated with specific biological behavior

Etymology: Frederick Lanchester, the British aerodynamicist and engineer, coined this term in his 1908 book "Aerodonetics," the second volume of a larger work on aerial flight. He needed a name for an aircraft's slow, rolling oscillation in which it climbs, loses speed, dips, and then climbs again, and he built it from Greek. In his preface he glossed it as "flight-like," from "phugē" and "eidos," and he took "phugē" to mean the act of flying. The Greek word actually meant "fleeing" or "escape," which is a related but different sense. Lanchester's mistake did not matter much, since the coinage stuck, but the word's first half carries an idea of flight-as-running-away rather than flight-as-aviation. The suffix "-oid" simply means "resembling," so the whole word means something like "resembling flight."