Definition
Two or more circles of different sizes that share the same center point.
Plain English
Circles drawn one inside another, all with the same middle point — like the rings of a target or the ripples from a single dropped pebble.
Context Anchor
Seen on aviation charts, airport diagrams, and cockpit map displays when circles are drawn around a point to show distance or areas.
Derivation
From Latin 'con-' meaning 'together' and 'centrum' meaning 'center.' Literally 'sharing a center' — which is exactly what the circles do.
Why Pilots Care
Allows quick visualization of distance rings or coverage areas around navigation aids during flight planning and situational awareness.
Analogy
Think of the rings on an archery target — different sizes, same bullseye in the middle.
Intuition Check
Concentric does not mean the circles are the same size. It means the circles have the same center point.
Example Sentence 1
The Class B airspace around the airport is depicted on the sectional as a series of concentric circles, each with its own altitude limits.
Example Sentence 2
The pilot used the concentric circles on the approach plate to judge remaining distance to the runway.