Friend: A person with whom one is on terms of mutual affection and respect.
Acquaintance: A person one knows slightly.
I'll add two more:
Relative: A person who is related by parentage or descent or marriage.
Stranger: A person one does not know.
Wouldn't it be nice if relationships were this easy to define? I have relatives who are friends and relatives who are strangers. I have acquaintances that I trust more than some relatives. I have friends that are sometimes strangers. I have friends who know it all. I consider some of my friends in the relative category.
The husband and I spent the weekend with friends. We all know way too much about each other but there's a level of trust there. We also know (or know about) each other's children and parents.
The words "trust" and "love" didn't show up in any of the definitions. Guess we get to define that for ourselves.