14 CFR § 1.3 - Rules of construction.

---
identifier: "/us/cfr/t14/s1.3"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "14 CFR § 1.3 - Rules of construction."
title_number: 14
title_name: "Aeronautics and Space"
section_number: "1.3"
section_name: "Rules of construction."
chapter_name: "FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION"
subchapter_number: "A"
subchapter_name: "DEFINITIONS AND GENERAL REQUIREMENTS"
part_number: "1"
part_name: "DEFINITIONS AND ABBREVIATIONS"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "49 U.S.C. 106(f), 40113, 44701."
cfr_part: "1"
---


# 1.3 Rules of construction.

(a) In this chapter, unless the context requires otherwise:

(1) Words importing the singular include the plural;

(2) Words importing the plural include the singular; and

(3) Words importing the masculine gender include the feminine.

(b) In this chapter, the word:

(1) *Shall* is used in an imperative sense;

(2) *May* is used in a permissive sense to state authority or permission to do the act prescribed, and the words “no person may * * *” or “a person may not * * *” mean that no person is required, authorized, or permitted to do the act prescribed; and

(3) *Includes* means “includes but is not limited to”.

[Doc. No. 1150, 27 FR 4590, May 15, 1962, as amended by Amdt. 1-10, 31 FR 5055, Mar. 29, 1966; FAA-2023-1275, Amdt. No. 1-78, 89 FR 92483, Nov. 21, 2024]