A determiner specifies a noun as known or unknown, and it goes before any modifiers (e.g. adjectives or other nouns).
Some examples of determiners are:
- articles (the, a or an)
- demonstratives (e.g. this, those)
- possessives (e.g. my, your)
- quantifiers (e.g. some, every).
- the home team [article, specifies the team as known]
- a good team [article, specifies the team as unknown]
- that pupil [demonstrative, known]
- Julia’s parents [possessive, known]
- some big boys [quantifier, unknown]
- home the team, big some boys [both incorrect, because the determiner should come before other modifiers]
'Determiner' is a word class label. It's a cover term for a range of word classes that are also known by other names, as the National Curriculum entry makes clear. Determiners typically occur before a noun within a noun phrase to indicate the type of reference the noun has, e.g. the, a/an, this, that, many, all. The so-called cardinal numerals, e.g. one, two, three, as in I ate three bowls of spaghetti, are sometimes included in the class of determiners. However, their classification is disputed, because there are also reasons for regarding them as nouns, for example the fact that we can pluralise them, as in They travelled in twos and threes. The ordinal numerals, e.g. first, second, etc. are adjectives. In a few cases determiners occur outside noun phrases, e.g. I don't like chocolate that much.