However, if you look it up in any dictionary, nowadays, the most common meaning is a set or unit of parents and children. This is the social base of the capitalism.
Capitalism is very old and natural.
Long ago, individuals and families realized that they do not have to produce everything they need by separated to live. But with the voluntary cooperation, either individually or by families you produce the goods or services you have comparative advantage and trade them by the ones you need. When this rudimentary trading got complicated, money was invented to facilitate it as an intermediate commodity and markets blossomed and capitalism was invented in a natural way. Prices were also an important tool to give an idea of how abundant and needed were these good or services and made the trading more efficient. However, capitalism would not have lasted this long if did not have the concept of family linked to it.