What is the difference between: "aquel" and "aquél"?

Question

I see both "aquel" and "aquél" used in similar context and was wondering if there is any difference in meaning of those two words.

Answer 1

aquel is a demonstrative adjective, and aquél is a demonstrative pronoun (used when the noun is not stated).

For example:

1) Ayer vi a aquel hombre. Yesterday I saw that man over there.

(demonstrative adjective, where aquel describes and proceeds the noun 'hombre´)

2) No quiero ese globo, sino aquél. I don't want that baloon, rather that other one over there.

(demonstrative pronoun, where aquél replaces the noun completely)

All of the demonstrative adjectives have an equivalent pronoun, shown with an accent mark (tilde):

Demonstrative Adjectives:

este estos

esta estas

ese esos

esa esas

aquel aquellos

aquella aquellas

Demonstrative Pronouns:

éste éstos

ésta étas

ése ésos

ésa ésas

aquél aquéllos

aquélla aquéllas

Answer 2

In Spanish we have what we called "tilde diacrítica" which is used to differentiate two words that are spelled the same but have different meaning. This is the case with "aquel" vs "aquél", the first one is a demonstrative adjective and the one with the accent mark is the demonstrative pronoun.