Air traffic clearance
14 CFR § 1.1 — Definitions
Official definition — 14 CFR Part 1
REGULATION — OFFICIAL DEFINITIONAir traffic clearance means an authorization by air traffic control, for the purpose of preventing collision between known aircraft, for an aircraft to proceed under specified traffic conditions within controlled airspace.
Reproduced verbatim from the eCFR. Regulatory definitions control how the term is used throughout 14 CFR.
Is this a regulation?
Yes — this is regulatory text and is legally binding.
Definition published in 14 CFR Part 1. Regulatory definitions are legally binding wherever the defined term is used in 14 CFR.