Plain English Meaning
Airspace where ATC is watching and giving instructions, so pilots must meet certain rules to fly in it.
Full Definition
In airspace terminology, designating airspace within which air traffic control (ATC) service is provided to participating aircraft, and within which specific entry, equipment, communication, and clearance requirements apply to pilots depending on the class of airspace.
Context Anchor
Seen in airspace discussions, especially when separating controlled airspace from uncontrolled airspace.
Derivation
From Latin contra-rotulus, meaning 'against the roll' — a roll being a record kept for checking. To 'control' originally meant to verify against an official record. In , controlled airspace is airspace where is checked and managed by ATC against a picture.