ქიმიის ტერმინთა განმარტებითი ლექსიკონი

Quantity, defined by a conventional measurement procedure, for which a total ordering relation can
be established, according to magnitude, with other quantities of the same kind of quantity, but for
which no algebraic operations among those quantities exist.

Example 1: Rockwell C hardness.
Example 2: Octane number for petroleum fuel.
Example 3: Earthquake strength on the Richter scale.
Example 4: Subjective level of abdominal pain on a scale from zero to five.

Note 1: Ordinal quantities can enter into empirical relations only and have neither measurement
units nor quantity dimensions. Differences and ratios of ordinal quantities have no physical meaning.