Office of the Federal Register (OFR)


1. Avoid unnecessary definitions.

The main purpose of a definition is to achieve clarity without needless repetition. For this reason, "it is unnecessary" to define ordinary words that are used in their usual dictionary meaning.

DON'T SAY: Trash can means a receptacle for waste material.

2. Do not define in a way that conflicts with ordinary or accepted usage.

If possible, use a word in a way that is consistent with the its everyday meaning and do not define the word. Otherwise, you confuse the reader and risk using the word elsewhere in your regulations in its ordinary sense.

DON'T SAY: Airplane means an airplane, helicopter, or hot-air balloon.

SAY: Aircraft means a device that is used or intended to be used for flight.

[Here the definition is broad enough to include any device that flies and at the same time the word is not used in a way that conflicts with its ordinary meaning.]

3. Do not define a term that is used only once or infrequently.

If a term is used only once or infrequently, spell out the meaning of the term at those few places it appears in the regulations.

4. Do not include part or all of the term being defined in the text of your definition.

A true definition should not include the term being defined as part of the definition. This forces the reader to consult a dictionary or look elsewhere in the regulations for the complete meaning.

DON'T SAY: Excepted position means a position in the excepted service.

5. Do not include a substantive rule within a definition.

A reader can easily miss a rule placed within a definition.

DON'T SAY: Sec. 200. Definitions. For the purpose of this part, alcoholic beverage means beer, wine, and liquor. Each owner of a business establishment serving alcoholic beverages shall obtain a license.

6. Place a definition where it is most easily found by the reader.

Generally, define a term that is used throughout a part or chapter at the beginning of that part or chapter. If you have a term that is used only once or in a few closely related sections, place the definition in the section where the term is used first.

7. Draft the regulations first, then draft the definitions.

It is difficult to determine how many times a particular word or concept will be used in a set of regulations before you start drafting. If you draft definitions before you draft your regulations, you may define a word that is not used.

Often a concept that is used in a set of regulations is complex and you must develop a phrase to use as shorthand for that concept. If you develop the phrase before you draft the regulations, the phrase may not be as appropriate as one developed during the process of drafting.

8. Do not use "must" in a definition.

The definition section of your regulations should not obligate anyone to do anything. For this reason, "must" is inappropriate for a definition. Instead, use the indicative mood.

DON'T SAY: Agency head must mean...

SAY: Agency head means...

9. List definitions as a group.

If you have a group of terms that you want to group together:

  • Place the terms in a section called "Definitions".
  • Place the defined terms in alphabetical order.
  • Do not give any defined term a paragraph designation, for example, (a), (b), (c); however, subordinate paragraphs are designated beginning with the following level, for example (1), (2), (3).


§ 100.3 Definitions.

For the purpose of this part --

Act means the Surface Mining Control and Reclamation Act of 1977.

OSMRE Director means the head of the Office of Surface Mining Reclamation and Enforcement.

Regional Director means the head of the Office of Surface Mining Reclamation and Enforcement in the region in which the state applying for a grant under this part is located.

This method of listing definitions makes your task easier if you ever have to add or remove definitions. You do not have to change the paragraph designation (known as redesignation) of each term that appears after terms are added or removed.