Demonstratives are words that indicate which objects a sentence is referring to. English has four demonstratives: this, that, these, and those.

Latin had several sets of demonstratives, including:

hic, haec, hoc

ille, illa, illud

iste, ista, istud

The second set, ille, etc., meaning that, developed into the definite articles in several Romance languages, such as el, la, los, las in Spanish, le, la, les in French and il, la, i, le in Italian.

Most European languages only make a two-way distinction between demonstratives, although how exactly these are divided can differ enough to confuse non-native speakers. Typically, one demonstrative indicates an object close to the speaker (English this, French celui-ci) and the other an object removed from the speaker (English that, French celui-là). Which to use when dealing with non-tangible objects (thoughts, concepts, emotions, etc) varies from language to language.

Some languages, most notably Japanese, but also some dialects of Jin Chinese, make a three way distinction. Typically, the third demonstrative is used to specify an object near the person being addressed. So for example, in Japanese:

kono ringo このりんご   'this apple'

sono ringo そのりんご   'that apple near you'

ano ringo あのりんご   'that apple far away from both of us'

It is relatively common for a language to distinguish between a determinative demonstrative and an independent demonstrative. English and Mandarin do not, but Japanese and French both do. A determinative demonstrative (c.f. determinative possessive) modifies a noun:

This apple is good.

An independent demonstrative (c.f. independent possessive) stands on its own, replacing rather than modifying a noun:

This is good.

In French, for example, you would say cette table-ci to mean this table, but celle-ci as an answer to the question Which table? Similarly, a Japanese person might respond to the question of Which apple? with simply one of kore これ, sore それ, or are あれ, depending on whether he meant 'this', 'that (near you)' or 'that (far from both of us)', respectively.