Definition
A pointed end or projecting point formed where two curves or surfaces meet at an angle, creating a sharp transition rather than a smooth blend.
Plain English
The sharp point you get where two curves come together and form a corner instead of flowing smoothly into each other.
Context Anchor
Seen in airframe maintenance descriptions, drawings, sheet-metal layout, and inspection notes that describe the shape of an edge, cut, or surface.
Derivation
From the Latin 'cuspis,' meaning a point or pointed end (like the tip of a spear). The original sense of a sharp point carries directly into the technical meaning.
Why Pilots Care
A sharp cusp on an aircraft part can be important because pointed shapes may need close inspection or careful finishing, especially where cracks or stress could start.
Analogy
Think of the pointed shape made when two ocean waves meet and peak together, or the sharp point at the corner of a crescent moon.
Intuition Check
Do not read cusp here as “being on the cusp of” something, meaning near a change. In airframe maintenance, it means a physical pointed shape or tip.
Example Sentence 1
The technician inspected the cusp where the two curved skin panels joined to make sure no cracks had formed at the point.
Example Sentence 2
A smooth cusp at the wing root fairing helps maintain airflow without creating drag.