A Best Friend is usually a chosen friend with whom one shares a deeper level of understanding, trust and affection than most others they are close to. The term is usually only used by children, in adulthood one may see all their friends as equal. However if they are especially close to someone who they are not romantically linked, they will not openly acknowledge them as a 'best friend'. Best friends usually share and enjoy the same activities, there may be some times when they share a valuable piece of information that may not be accessible to others.
Someone who is a friend of a particular person who has another 'best friend' may become jealous of that person, particularly if the child is older and different genders are involved.
In today's scenario, people from two different genders can become the 'best of friends' or best friends.
