Friends are people we mix around with and I daresay that we have many types of friends whom we could put into various circles. E.g. work friends, family friends, close friends, casual friends and bosom pals.
Work friends are those whom we meet daily at work and over time have become friends. Casual friends are more of acquaintances whom we meet from time to time and engage in small talk with. Family friends are friends of the family. They could be your parents’ friends or friends who have become close to your family and are highly regarded.
Close friends are those with whom you have a very good relationship and you trust and support one another. Close friends are often friends who go back a long way, e.g. since school days. They may not be many and often can be counted on one hand only. If you’re very lucky, then two hands. As Shakespeare said of good friends in his play "Hamlet", we should should grapple them to our souls with hooks of steel.
Bosom friends are very close friends whom you share confidences with and whom you know will never disclose your secrets. They are the tried and tested pals who also go back a long way although not necessarily so. The main thing is that you trust your bosom pal and you would stick by each other through thick and thin. Usually your bosom friend is only one or at most two.
Your bosom friend can also be your sibling.
As we grow older we realize how important our friends are, especially close friends. They make the difference to an otherwise lonely existence. However, know that friendships are like flowers in a garden which need to be nurtured in order to grow.
May your friendships be a lovely garden full of flowers.