A grammatical category is a semantic distinction which is reflected in a morphological paradigm. Grammatical categories can have one or more exponents. For instance, the feature [number] has the exponents [singular] and [plural] in English and many other languages. (See grammatical number

Grammatical number

In linguistics, grammatical number is a grammatical category of nouns, pronouns, and adjective and verb agreement that expresses count distinctions ....

.) The members of one category are mutually exclusive; a noun cannot be marked for singular and plural at the same time, nor can a verb be marked for present and past at the same time. Exponents of grammatical categories are often expressed in the same position or 'slot' (prefix

Prefix

A prefix is an affix which is placed before the root of a word. Particularly in the study of languages,a prefix is also called a preformative, because it alters the form of the words to which it is affixed.Examples of prefixes:...

, suffix

Suffix

In linguistics, a suffix is an affix which is placed after the stem of a word. Common examples are case endings, which indicate the grammatical case of nouns or adjectives, and verb endings, which form the conjugation of verbs...

, enclitic, etc.). Some examples of this are the Latin cases

Latin declension

Latin is an inflected language, and as such has nouns, pronouns, and adjectives that must be declined in order to serve a grammatical function. A set of declined forms of the same word pattern is called a declension. There are five declensions, which are numbered and grouped by ending and...

, which are all suffixal: ros, ros, ros, ros, ros. ("rose", in nominative, genitive, dative, accusative, ablative)

For example, in English

English language

English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...

, the grammatical number

Grammatical number

In linguistics, grammatical number is a grammatical category of nouns, pronouns, and adjective and verb agreement that expresses count distinctions ....

 of a noun

Noun

In linguistics, a noun is a member of a large, open lexical category whose members can occur as the main word in the subject of a clause, the object of a verb, or the object of a preposition .Lexical categories are defined in terms of how their members combine with other kinds of...

 such as bird in:

• The bird is singing.
• The bird are singing.

is either singular or plural, which is expressed overtly by the absence or presence of the suffix -s. Furthermore, the grammatical number is reflected in verb agreement

Agreement (linguistics)

In languages, agreement or concord is a form of cross-reference between different parts of a sentence or phrase. Agreement happens when a word changes form depending on the other words to which it relates....

, where the singular number triggers is, and the plural number, are.

Grammatical categories are often expressed by affix

Affix

An affix is a morpheme that is attached to a word stem to form a new word. Affixes may be derivational, like English -ness and pre-, or inflectional, like English plural -s and past tense -ed. They are bound morphemes by definition; prefixes and suffixes may be separable affixes...

es, but clitic

Clitic

In morphology and syntax, a clitic is a morpheme that is grammatically independent, but phonologically dependent on another word or phrase. It is pronounced like an affix, but works at the phrase level...

s and particles are also common.

See also

• Grammatical function
  Grammatical function
  In linguistics, grammatical functions refer to functional relationships between participants in a proposition...
  
  
• Grammeme
  Grammeme
  A grammeme in linguistics is a unit of grammar, just as a lexeme is a lexical unit and a morpheme is a morphological unit.More specifically, a grammeme is a value of a grammar category. For example, singular and plural are grammemes of the category Grammatical number, noun and verb are grammemes of...
  
  
• Inflection
  Inflection
  In grammar, inflection or inflexion is the modification of a word to express different grammatical categories such as tense, grammatical mood, grammatical voice, aspect, person, number, gender and case...
  
  
• Lexical category
  Lexical category
  In grammar, a part of speech is a linguistic category of words , which is generally defined by the syntactic or morphological behaviour of the lexical item in question. Common linguistic categories include noun and verb, among others...
  
   (part of speech)
• Syntax
  Syntax
  In linguistics, syntax is the study of the principles and rules for constructing phrases and sentences in natural languages....