The traditional grammatical classes of words are called "parts of speech". Since the word is distinguished not only by grammatical, but also by semantico-lexemic properties, some scholars refer to parts of speech as "lexico-grammatical" series of words, or as "lexico-grammatical categories". It should be noted that the term "part of speech" is purely traditional and conventional. In modern linguistics, parts of speech are discriminated on the basis of the three criteria: "semantic", "formal", and "functional". The semantic criterion presupposes the evaluation of the generalised meaning, which is characteristic of all the subsets of words constituting a given part of speech. The formal criterion provides for the exposition of the specific inflexional and derivational (word-building) features of all the lexemic subsets of a part of speech. The functional criterion concerns the syntactic role of words in the sentence typical of a part of speech. The said three factors of categorial characterisation of words are conventionally referred to as, respectively, "meaning", "form", and "function".
To the notional parts of speech of the English language belong the noun, the adjective, the numeral, the pronoun, the verb, the adverb.
The features of the noun within the identificational triad "meaning — form — function" are, correspondingly, the following: 1) the categorial meaning of substance ("thingness"); 2) the changeable forms of number and case; the specific suffixal forms of derivation; 3) the substantive functions in the sentence (subject, object, substantival predicative); prepositional connections; modification by an adjective. The features of the adjective: 1) the categorial meaning of property (qualitative and relative); 2) the forms of the degrees of comparison (for qualitative adjectives); the specific suffixal forms of derivation; 3) adjectival functions in the sentence (attribute to a noun, adjectival predicative).
The features of the