Before we reveal the answer, let us check its evolution history first (image get from http://www.vividict.com)
|Learn one Chinese Character a day - 家|
In ancient China, pig was one of the most important asset of a family. People raised their pigs inside their house, where their family lives. Thus Chinese ancestors used to represent the meaning of home.
So 家 means home.
家 is also extended to mean a family, or a faction of people.
As 家 has the meaning of raising pigs at home, which was a skillful job in ancient time, 家 is thus used to mean a specialist or expert as well.
Now let us enjoy a Chinese calligraphy with 家 inside: