Sections.
CFR · 2024-01-01 · US · Title 1
(a) The normal divisions of a part are sections. Sections are the basic units of the Code. (b) When internal division is necessary, a section may be divided into paragraphs, and paragraphs may be further subdivided using the lettering indicated in § 21.11.
official document · source cfr-2024 · id 1:§ 21.10