Introduction

General Terms

Culture:

Culture is the characteristics and knowledge of a particular group of people, defined by everything from language, religion, cuisine, social habits, music and arts.

According to the UNESCO:
Culture is that complex whole which includes knowledge, beliefs, arts, morals, laws, customs, and any other capabilities and habits acquired by [a human] as a member of society.

A Culture can be defined by its food, tradition, dance, fashion, among other characteristics. Some examples of cultures are: Japanese, Brazilian, French, our Costa Rican culture and many others.

Subculture:

A cultural group within a larger culture, often having beliefs or interests at variance with those of the larger culture.

A branch off from mainstream culture embracing it's own unique style. Often times, as more and more people do it, pieces of various subcultures become mainstream.

UNESCO says that the term sub-culture is used to refer to minority cultures within a larger dominant culture. 

Some examples may be: Gothic, Hipster, cosplayer, gamer, etc.

Clique:

A small close-knit group of people who do not readily allow others to join them.

Some common examples are Jocks and Cheerleaders.

This is common in high schools among different groups. Althought this is changing nowadays allowing inclusion in this groups.