The Catechism in Questions & Answers

407. Why are there different Christian denominations?

The multiplicity of Christian communities (denominations) has come about owing to varying interpretations of the gospel, as well as cultural, social, and historical differences.

Denomination: see explanation of Question 365.

Anything formed by human beings can, in the broadest sense, be described as ‘culture’. People and nations have differing cultural features owing to their way of life, their history, their experiences, their religious and political origins, their customs, their worldviews and convictions, etc.
The word ‘social’ derives from the Latin word socius and means “together”, “united”, or “allied”. We use it when we want to express that an individual is interconnected with his neighbour and the community, and cares about others.