What word means “the people in one's life”?

I am looking for the closest single word which refers only to those people who are directly connected to a person's life. Most specifically, this the meaning of the word should include co-workers, classmates, friend, and family members, but should not include strangers.

How about kith? I had always assumed that kith excluded family members (because of the phrase "kith and kin") but it seems to have about the definition and connotation you desire.

Definition of KITH: familiar friends, neighbors, or relatives

Of course the word isn't commonly used outside of that one particular phrase, but still, it seems to fit.

Here's the etymology of it.

That would probably be your circle, a term that Google also uses. You can also consider the words coterie, tribe, and clan.

Community is broad enough to encompass co-workers and friends, and intimate enough to include family.

community (noun) 1. a social group of any size whose members reside in a specific locality, share government, and often have a common cultural and historical heritage.

2.a social, religious, occupational, or other group sharing common characteristics or interests and perceived or perceiving itself as distinct in some respect from the larger society within which it exists.