A demonstrative pronoun in grammar and syntax is a pronoun that shows the place of something.
In English, a demonstrative pronoun may be definite or indefinite. Definite demonstratives are the words: this, that, these, those, one, ones, none, such. They serve the function of pointing to the ancedent and demonstrate how close something is (proximity). Demonstrative pronouns can be singular, such as this and that, however most demonstrative pronouns are plural, and they generally stand in for a noun phrase. Indefinite demonstrative pronouns are these: each, either, neither, everyone, everything, anybody, some, many and one. They function as substitutes for a noun that is understood or implied but they generally have no specific antecedent in mind.
An example
Take the sentence "The cow jumped over the moon" and make the object of that sentence the subject of a new more complex sentence, like this: "The moon that the cow jumped over, was full."
e demonstrativepronouns can be used for both pointing and identifying a noun or something, and also to refer to the distance among “the thing”, the speaker and the listener.
For example, in English, the demonstrativepronouns “this” and “these” refer to things that are close to the speaker while the pronouns “that” and “those” refer to things that are further away from the speaker, in space or time.
In Spanish the demonstrativepronouns must agree in gender and number with the noun the pronoun is related to.
Demonstratives are deictic words (they depend on an external frame of reference) that indicate which entities a speaker refers to, and distinguishes those entities from others.
Demonstratives are usually employed for spatial deixis (using the context of the physical surroundings), but in many languages they double as discourse deictics, referring not to concrete objects but to words, phrases and propositions mentioned in speech.
In Spanish the difference is less marked; except for the series of singular neuter independent pronouns (esto, eso, aquello), the rest of the demonstrativepronouns are identical to the adjectives (except in writing, where a diacritic accent mark is used to mark the pronouns).