Definitions of 'culture' vary in both complexity and the attributes that are emphasised.

Some examples are:

• A culture is a LIFESTYLE shared by a large GROUP of people
• Culture is what is TAUGHT by a large GROUP to its members
• Culture is the FILTER through which we see 'reality'

A culture is identified when a large group of people share a distinctive set of:

• Manners (CUSTOMS, practices, rules)
• Morals (VALUES, BELIEFS, norms)
• ARTS (visual, literary, performing, aural, etc)
• Traditions including KNOWLEDGE and HISTORY

Additional notes:
It doesn't matter which definition you prefer, but it is important to remember that:

• Culture describes the group, not the individuals in it; so, not all members of the group agree about manners, morals, arts and traditions, about what the lifestyle is, about what should be taught to the members of the group. For example,racing, rugby and beer and quarter-acre, half-pint, Pavlova paradise are expressions which have been used to describe New Zealand culture, but many New Zealanders are not interested in one or more of these aspects of New Zealand life.
• Cultures are changing all the time as they influence each other and respond to changes in the environment. Sometimes it is hard to distinguish between cultures because of overlap resulting from ongoing interaction amongst the members; for example, some people find it difficult to distinguish between New Zealand and British cultures.
• Membership of a cultural group is based on your behaviour and beliefs, not on inherent characteristics such as actual age, gender, race, sexual practices, occupation, citizenship etc. Being a member of a culture means that you understand how and why the group acts as it does and you know enough to be able to operate competently within it yourself Usually, people live within the cultures of which they 'appear' to be members. For example, most people aged between 13 and 19 prefer teenage language, dress codes, music, but some people in the age group prefer older or younger cultural lifestyles and some outside that age group adopt the teenage lifestyle - both of which may be very disconcerting to others who expect them to act according to their chronological age.
• In society, some cultural groups have more power/authority than others and this encourages some people to learn/adopt those cultures. For example, some women have learned to operate within a heterosexual male culture because they are more likely to get good jobs that way; many Maori have adopted Pakeha culture.
• Sub-cultures are smaller groups within a larger culture. Nobody has ever defined how big a group has to be to constitute a culture or sub-culture, but usually either would include thousands rather than dozens of people. For example, New Zealand culture includes Maori, Pakeha, Pasifika and Asian cultures; Maori culture includes many Iwi such as Nga Puki, Ngati Porou, Kai Tahu; Pakeha culture includes people identifying as Irish, as Dutch, as Dalmatian, etc; Pasifika culture in New Zealand includes Samoan, Tongan, Cook Island cultures; and of course there are many Asian cultures as well. Some of the large sub-cultures even have sub-cultures within them, for example, Christianity includes both Catholics and Protestants; Protestants include Presbyterians, Mormons, Methodists and so on.