Definition
A measuring surface marked with a series of evenly spaced lines and numbers used to read a value directly. On a magnetic compass, it is the printed scale around the compass card showing headings in degrees from 0 through 359, usually marked every 5 degrees with numerals shown every 30 degrees.
Plain English
A scale with regular tick marks and numbers on it, like a ruler, that lets you read off an exact value. On a compass, it is the ring of degree markings you read to see which way the aircraft is pointing.
Context Anchor
Seen on the magnetic compass when reading or checking the airplane’s compass direction.
Derivation
From Latin gradus, meaning 'step.' A graduated scale is literally a scale built in steps -- evenly spaced increments you can count along.
Why Pilots Care
Enables accurate determination of aircraft heading without estimation or guesswork.
Analogy
Like the markings on a ruler or a kitchen measuring jug -- the value you want is read directly off the line nearest the pointer.
Intuition Check
“Graduated” does not mean finishing school here, and “scale” does not mean a weighing device. In this context, a graduated scale means a set of measurement marks divided into steps.
Example Sentence 1
The pilot read 270 degrees off the graduated scale on the compass card, confirming a westerly heading.
Example Sentence 2
During the compass swing, the technician verified each marking on the graduated scale against known headings.