Definition
The Code of Federal Regulations is the official compilation of rules issued by U.S. federal agencies. For aviation, Title 14 of the CFRs (commonly written as 14 CFR) contains the rules governing aircraft, airmen, and operations, including the parts pilots refer to most often such as Part 61 (certification of pilots), Part 91 (general operating and flight rules), Part 121 (airline operations), and Part 135 (commuter and on-demand operations).
Plain English
The CFRs are the official rulebook of the U.S. government. The aviation section of that rulebook is what pilots have to follow.
Context Anchor
You will see CFRs cited in FAA handbooks, checklists, training material, operating rules, and discussions of what is legally required before or during a flight.
Derivation
Code' here means an organized collection of laws or rules, from the Latin 'codex' (a book or set of writings). 'Federal' refers to the U.S. national government. So the term simply means 'the national government's organized book of rules.'
Why Pilots Care
Pilots must operate within these regulations to maintain legal flight status and ensure safety.
Intuition Check
Do not treat CFRs as general advice or handbook guidance. In this context, CFRs means the actual federal rules that carry legal force.
Example Sentence 1
Before the checkride, she reviewed the relevant sections of the CFRs covering currency and medical requirements.
Example Sentence 2
Understanding the CFRs helps avoid violations during in-flight operations.