Names and Patterns

Display Names

These are intended for stand-alone use such as the label of a field where values may be entered, for example Minutes and Seconds in the example below.

Enter desired time to liftoff:
 Minutes:    Seconds:  

The expectation is that the display names would be in nominative form for languages in which it makes a difference. There may be cases in which a display name could be used in contexts for which nominative would be inappropriate, but the hope is that CLDR clients would arrange the use of display names in user interfaces so that nominative form is not inappropriate.

The unit data is provided in three widths:
  • long: typically a fully spelled-out name
  • short: a distinctive abbreviated form, not easily confused with another unit
  • narrow: as short as possible for situations with limited display space. Typically this form eliminates spaces and punctuation to the extent possible, and uses abbreviations that might only be clear in context.
Note that if in your locale certain abbreviations are always understood to mean particular units, then different abbreviations should generally be used even in the narrow form for other units. For example, if “m” is always understood to mean “meters”, then even in the narrow form a different abbreviation should be used for “minutes”—perhaps “min”, “mn”, or even “m.”.

Simple Units

Simple units are cases like "{0} mile" or "{0} miles". These have from 1 to 6 plural forms, depending on the language. Units also have a display name, such as "miles", used as labels in interfaces.

Compound Units

Some units are compound units, like "miles per hour". When formatting, software will first look for a specialized pattern (with the right plural form), then if that is not available, look for a compound unit and compose a fallback format. There are currently two such patterns:

per cm/s
centimeters per second
Used to compose units consisting of a division of two source units. See perUnitPatterns.
times kW⋅h
Used to compose units consisting of a multiplication of two source units. See kilowatt hour.

The specialized patterns are needed where there is a special abbreviation, like "mph" instead of "m/hr".

Specialized Pattern

In addition, there are some very common combinations that are translated as a whole, such as "{0} kilometro par hora". In that case, the number is substituted directly for the {0} placeholder.

Per Unit Pattern

In many languages, the "per Y" part is inflected, and the dividing unit can't be simply substituted for {1}. Because of that, there are "per unit" patterns that are of the form "{0} per hour". For that case, the process is simpler. The first two steps are the same, but then the result is substituted into the "{0} per hour" pattern directly.

Fallback Format: two units

Some units are formed by combining other units. The most common of this is X per Y, such as "miles per hour". There is a "per" pattern that is used for this. For example, "{0} per {1}" might get replaced by "10 meters per second". 

Given an amount, and two units, the process uses the available patterns to put together a result, as described on perUnitPatterns. (e.g. "3 kilograms" + "{0} per second" → "3 kilograms per second")