I need a pair of adjectives (or adjectival phrase) to distinguish between two types of data associated with a thing. On the one hand are attributes that occur only once, and can be defined as a 1:1 relationship between a label and its content; on the other are sets of attributes that can recur, and are really lists of things, each entry of which has its own set of attributes.

That’s not at all clear, so to make it concrete, consider a car. There are certain attributes that exist only once: its vehicle identification number, its year, its manufacturer (e.g. “Toyota”), its model designation (“Corolla”). That’s the first category.

On the other hand, the car’s maintenance record is a list of events. For example, if the car was taken in for an oil change (maintenance activity) on January 2, 2015 (date) at Mac’s garage (servicer); and taken in for a headlight replacement (maintenance activity) on March 8, 2015 (date) at Cars-R-Us (servicer). You have two maintenance events. That’s an example of the second category, where there can be more than one.

There can be multiple things in the second category, too. I’ve already given an example of maintenance events, but another might be ownership. It could have, say, 4 or 5 owners during its lifetime.

So I’m looking for a good adjective to distinguish between those one-of-a-kind attributes; and those attributes that can occur multiple times.

  • This may not be an exact match, but adjectives may be classifying (a nuclear reaction), identifying (mine is the red car) or qualitative (a red car). As seen, the sets are not disjoint. May 10, 2016 at 23:40
  • Thanks. I don't think that really gets me there. Some of the one-off attributes are indeed identifying (the VIN in this example), but the rest are qualifying, regardless of which side of the distinction they fall. Although within the second category, if we added a sequence #, arguably the sequence would be identifying; but that still doesn't give me a good label for the one-off vs. the recurring. (I am using "one-off" and "recurring" as placeholders now, which I really don't like, but may give a better flavor for the distinction I'm looking for.)
    – codingatty
    May 11, 2016 at 0:04
  • 1
    Perhaps unary and multiplex. May 11, 2016 at 0:12
  • I'd be tempted to call the 1:1 items particulars. A VIN number is particular to one vehicle (but the reverse is not always true). Particulars usually get listed on the master record. The rest depend on the organization scheme. In real estate tax, the current description of each building located on a property is still called a card. There can be any number of them. Logbook entries record events.
    – Phil Sweet
    May 11, 2016 at 0:13
  • Royals and Menials
    – vickyace
    May 11, 2016 at 0:50

4 Answers 4


I'll give an example from computer science.

The first kind (1:1) is an attribute. It definitively describes the object.

The second kind (1:N) is an association. It indicates a relationship between the object (the car) and something else (the service visit).


I don't know of any words that are an exact match to the question (esp. with regard to the singular vs. multiple aspect of attributes.) But based on the examples given, perhaps this dichotomy could work:

There are defining attributes which are essential to the identity of a concept. For example, the concept "black cat" must have a color attribute of "black." A "black cat" that has a color attribute of "orange" is no longer a "black cat." In the car example, all the examples of the first category are defining attributes.

There are also qualifying attributes which don't define an object, but add information about it. These attributes are not essential and can change values without changing the essence of the object. A black cat can be male of female (or hungry or full, or thin or fat, etc.) without changing its essential nature.

Defining vs. qualifying are the terms I've learned and that I hear used the most. The only online reference I can find uses "essential" vs. "accidental" to describe the same distinctions:


As an aside, the difference between "that" and "which" follows the same dichotomy. (See http://grammarist.com/usage/which-that/)


I like this answer less than the other one I've posted. I'm adding it to try to get closer to addressing the multiple vs. singular aspect of the question. I don't know if it answers the question exactly; I don't know if a more exact answer exists.

In computer modeling, attributes themselves have an attribute called "cardinality." Cardinality does describes the distinction the OP is looking for.

For example, the "current height" and "current weight" attributes of a person have a cardinality of one: A person can only have one of these at any one time. The attributes listed in the OPs examples of the first category have a cardinality of one.

The "phone number" attribute of a person has a cardinality of "many" since a person can have many different phone numbers. The other attributes of cars listed by the OP have a cardinality of "many."

See "cardinality restraints" in section 3.1.2 of the following resource. It's highly technical and abstract:



You've asked for two adjectives, but I'm going to give you four: static, dynamic, sequential and temporal.

A static attribute is one which, once established, never changes. This kind of attribute can easily be represented by an immutable property.

A dynamic attribute is one which can be changed. This kind of attribute can easily be represented by a mutable property.

A sequential attribute is a mutable property which retains its prior values. This kind of attribute can easily be represented as an ordered list.

A temporal attribute is a sequential attribute that also remembers when new values are established. This kind of attribute can easily be represented as a timestamped list.

"Static" and "dynamic" are direct antonyms, but I recommend using "static" and "temporal" to describe the two kinds of data storage in your model.

A car's VIN and a person's birth date are static. A car's current color or a person's current employer are dynamic. A car's maintenance history and a person's employment history are temporal. It is always possible to store dynamic attributes as temporal data. To determine a car's current color, for example, you can reference the most recent entry of the car's color history.

As a side note, a name should not be implemented as static data. That may seem obvious in the case of unmarried women, but it's just as true in the case of car manufacturers -- consider the example of rebranding Datsun as Nissan in the American market in the 1980's.

  • "Static" and "Sequential" may be approaching what I'm looking for. "Temporal" isn't really it; that seems to suggest a single value capable of change; i.e. "last oil change". I'm thinking of, for example, tracking all the oil changes. Let me mull on this. Still not an answer that completely captures what I'm looking for, but I'm starting to think that one doesn't exist.
    – codingatty
    Jun 11, 2016 at 0:28
  • If the data set is merely sequential, then all you have is an ordered list: a tire rotation, an oil change, another oil change, a replaced windshield -- nothing that tells you when, merely how many and in what order. The data set you're thinking about is temporal: a tire rotation and oil change on January 8, another oil change on March 27, a replaced windshield on August 3. "Temporal" means "related to time" -- by definition temporal data includes timestamps in its keys. With temporal data, you can know how many entries were made in March, or how long it's been since the last oil change. Jun 11, 2016 at 5:28

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