Property Names

The following provides rules and guidance for naming properties.


A single NIEM component name may consist of multiple terms. A term is a meaningful word, an abbreviation for a word, or an acronym.

OED Terms

Besides the additional accepted terms listed below, terms should be real words as defined by the Oxford English Dictionary.


For consistency, words should use the preferred U.S. spelling as defined in the Oxford English Dictionary.

Additional terms

Additional terms that may be used are:

  • ID, the authorized abbreviation for Identifier
  • URI, the authorized abbreviation for Uniform Resource Identifier
  • Local terminology, defined by a NIEM namespace.

Parts of a name

In accordance with IEC/ISO 11179 Part 5, terms that make up a NIEM property name are classified into four basic parts according to their placement and function:

  • Object
  • Qualifier
  • Property
  • Representation

Object term

An object term is the real world object or concept to which this name applies. This may be omitted if the property is very generic and no specific class applies.

  • AircraftFuselageColorCode - a color of the main body of an aircraft.
  • Aircraft is the object term. In this example, that is the object being modeled.

Qualifier term

A qualifier term indicates more specific information applicable to the object, property, or representation term.

  • Multiple qualifier terms may be used if needed.
  • Qualifiers are optional.
  • AircraftFuselageColorCode - a color of the main body of an aircraft.
  • Fuselage is a qualifier term. In this example, it describes what kind of color is expected.
  • A related element in NIEM is AircraftWingColorCode. Wing would be the qualifier term in that example.

Property term

A property term is the characteristic, or portion of the object, to which this name applies.

  • AircraftFuselageColorCode - a color of the main body of an aircraft.
  • Color is the property term. This is the primary characteristic of the property name. The value of this property will be a color.

Representation term

A representation term indicates the kind of value a property carries.

  • A representation term, if present, must appear as the final term of the name.
  • Representation terms are required for properties that carry a simple value, like a string or a number.
  • Representation terms are required for other properties with specific types.

See the Reference Table for the list of representation terms.

  • AircraftFuselageColorCode - a color of the main body of an aircraft.
  • Code is the representation term. It indicates the general kind of value to expect.

Restricted terms


Avoid use of the term Type. Type is reserved as the representation term for NIEM types; it indicates a structure. Properties should use the term Category instead to represent type / category / kind.

NIEM does allow for exceptions when the use of the term Category causes confusion over very well-known concepts that use the term type. One such exception is for the element j:PersonBloodTypeCode.


Avoid use of the term Number in data names. Its use is usually too generic to be meaningful or helpful. A number should usually be an ID (Identifier), Quantity, Numeric (or Value), Amount, Measure, or Duration (of time).

Other guidance

No double terms

Do not use double terms (i.e., consecutive identical or similar terms such as IDID or NumberNumeric). Double terms should be replaced with a single instance of the term if it makes sense to do so.

This can sometimes cause different parts of a name, like the property term and the representation term, to be combined into one.

ID vs Identification

In NIEM, ID is used as the abbreviation for Identifier. This term is used for simple properties; it represents a unique string or number.

NIEM uses Identification as the representation term for a complex representation of an ID. This term carries a unique string or number, and additional information, like expiration date and the issuer. It is typically used by properties with the type nc:IdentificationType.


Rule Applicability Title
NDR 10-44 REF, EXT Schema component name composed of English words
NDR 10-45 REF, EXT Schema component names have only specific characters
NDR 10-46 REF, EXT Punctuation in component name is a separator
NDR 10-47 REF, EXT Names use camel case
NDR 10-49 REF, EXT Name of schema component other than attribute and proxy type begins with upper case letter
NDR 10-50 REF, EXT Names use common abbreviations
NDR 10-53 REF, EXT Singular form is preferred in name
NDR 10-54 REF, EXT Present tense is preferred in name
NDR 10-55 REF, EXT Name does not have nonessential words
NDR 10-56 REF, EXT Element or attribute name follows pattern
NDR 10-57 REF, EXT Object-class term identifies concrete category
NDR 10-58 REF, EXT Property term describes characteristic or subpart
NDR 10-59 REF, EXT Name may have multiple qualifier terms
NDR 10-60 REF, EXT Name has minimum necessary number of qualifier terms
NDR 10-61 REF, EXT Order of qualifiers is not significant
NDR 10-62 REF, EXT Redundant term in name is omitted