The essence of the category of number is to show the difference in quantity of things, namely: one thing – more than one thing.

Recently a peculiar view of the category of number was put forward by A. Isachenko.² According to this view, the essential  meaning of the category (in nouns) is not that of quantity, but of discreteness (расчлененность). The plural, in this view, expresses fundamentally the notion of something consisting of distinguish able parts, and the meaning of quantity in the usual sense would then appear to be a result of combining the fundamental meaning of the category as such with the lexical meaning of the noun used in the plural. Thus, in scissors the category of plural number, which, in Isachenko's view, expresses discreteness, combines with the lexical meaning of the noun, which denotes an object consisting of two halves, whereas in houses the same meaning of the grammatical category combines with the lexical meaning of the noun, which denotes separate objects not coalescing together, as in the case of scissors. Accordingly, the resulting meaning is that of a number of separate objects, i. e. the plural number in the usual sense of the term.

The productive model is forming the plural by adding the ending -s.

There are also non-productive models that are characteristic only of the existing in the language words. Here belong suffixes the use of which is limited to definite words: a) the suffix -en in oxen, children; b) suffixes of the words of the Latin origin: -i in nucleus – nuclei, -a in stratum – strata, symposium – symposia, genus – genera, phenomenon – phenomena, -ae in antenna – antennae. - assimilation the plural ending -s. Thus, instead of the traditional opposemes medium – media, or formula – formulae, new opposemes are developed with the second member inflected -s: mediums, formulas, terminuses, antennas c) the vowel change: tooth – teeth, mouse – mice, woman – women, man – men, foot – feet, etc.

Common number with uncountable singular nouns can also be expressed by means of combining them with words showing discreteness, such as bit, piece, item, sort. Cf.: The last two items of news were quite sensational.

The absolute singular is characteristic of the names of abstract notions {peace, love, joy, courage, friendship, etc.), the names of the branches of professional activity {chemistry, architecture, mathematics, linguistics, etc.), the names of mass-materials {water, snow, steel, hair, etc.), the names of collective inanimate objects {foliage, fruit, furniture, machinery, etc.). Some of these words can be used in the form of the common singular with the common plural counterpart, but in this case they come to mean either different sorts of materials, or separate concrete manifestations of the qualities denoted by abstract nouns, or concrete objects exhibiting the respective qualities.

It is sometimes stated that the plural form indiscriminately presents both multiplicity of separate objects ("discrete" plural, e.g. three houses) and multiplicity of units of measure for an indivisible object ("plural of measure", e.g. three hours)

The absolute plural is characteristic of the uncountable nouns which denote objects consisting of two halves (trousers, scissors, tongs, spectacles, etc.), the nouns expressing some sort of collective meaning, i.e. rendering the idea of indefinite plurality, both concrete and abstract (supplies, outskirts, clothes, parings; tidings, earnings, contents, politics; police, cattle, poultry, etc.), the nouns denoting some diseases as well as some abnormal states of the body and mind (measles, rickets, mumps, creeps, hysterics, etc.). As is seen from the examples, from the point of view of number as such, the absolute plural forms can be divided into set absolute plural (objects of two halves) and non-set absolute plural (the rest).